CS计算机代考程序代写 Microsoft PowerPoint - 11a_StructureMemory.pptx

Microsoft PowerPoint – 11a_StructureMemory.pptx

CS 2211
Systems Programming

Part Ten – A
Structures and Memory

void swap_value(int va, int vb) {
int vTmp = va;
va = vb;
vb = vTmp;

}

void swap_reference(int *ra, int *rb) {
int rTmp = *ra;
*ra = *rb;
*rb = rTmp;

}

int main()
{

int a = 1;
int b = 2;
printf(“before swaps: a = %d\n”, a);
printf(“before swaps: b = %d\n”, b);
swap_value(a, b);
printf(“after swap_value: a = %d\n”, a);
printf(“after swap_value: b = %d\n”, b);

swap_reference(&a, &b);
printf(“after swap_reference: a = %d\n”, a);
printf(“after swap_reference: b = %d\n”, b);

}

POINTERS Passing Values TO and FROM a Function

pass-by-value
verus

pass-by-reference

void swap_value(int va, int vb) {
int vTmp = va;
va = vb;
vb = vTmp;

}

void swap_reference(int *ra, int *rb) {
int rTmp = *ra;
*ra = *rb;
*rb = rTmp;

}

int main()
{

swap_reference(&a, &b);
printf(“after swap_reference: a = %d\n”, a);
printf(“after swap_reference: b = %d\n”, b);

}

POINTERS Passing Values TO and FROM a Function

Label Address Value

a 400 – 403 1
b 404 – 407 2
va 512 – 515 1
vb 516 -519 2

( 1, 2 )

call frame (main)

void swap_value(int va, int vb) {
int vTmp = va;
va = vb;
vb = vTmp;

}

void swap_reference(int *ra, int *rb) {
int rTmp = *ra;
*ra = *rb;
*rb = rTmp;

}

int main()
{

swap_reference(&a, &b);
printf(“after swap_reference: a = %d\n”, a);
printf(“after swap_reference: b = %d\n”, b);

}

POINTERS Passing Values TO and FROM a Function

Label Address Value

a 400 – 403 1
b 404 – 407 2
ra 512 – 515 400
rb 516 -519 404

( 400, 404 )

call frame (main)

1 2

3 4

typedef struct human {
char first[32]; /* 1st field is array of char */
char last[32]; /* 2nd field is array of char */
int year; /* 3rd field is int */
} person; /* alias for human UDT ; */

int main()
{

person teacher;

teacher.year=2025;
strcpy(teacher.first,”Sam”);
strcpy(teacher.last,”Maggs”);

DisplayStats(teacher);
printf(“%s\n”,teacher.first);

return 0;
}

POINTERS Passing Values TO and FROM a Function

typedef struct human {
char first[32]; /* 1st field is array of char */
char last[32]; /* 2nd field is array of char */
int year; /* 3rd field is int */
} person; /* alias for human UDT ; */

int main()
{

person teacher;

teacher.year=2025;
strcpy(teacher.first,”Adam”);
strcpy(teacher.last,”Hoover”);

DisplayStats(teacher);
printf(“%s\n”,teacher.first);

return 0;
}

POINTERS Passing Values TO and FROM a Function

Address Label Label Address Value

teacher
teacher.first teacher.first[0]

400 –
S

teacher.first[1] 401 – a
teacher.first[2] 402 – m
teacher.first[3] 403 – \0
teacher.first[5] 404 –
teacher.first[6] – [31] 405 – 431

teacher.last teacher.last[0] 432 – M
teacher.last[1] 433 – a
teacher.last[2] 434 – g
teacher.last[3] 435 – g
teacher.last[4] 436 – s
teacher.last[5] 437 – \0
teacher.last[5] 438 –
teacher.last[6] – [31] 439 – 463
teacher.year 464 – 467 2025

typedef struct human {
char first[32]; /* 1st field is array of char */
char last[32]; /* 2nd field is array of char */
int year; /* 3rd field is int */
} person; /* alias for human UDT ; */

int main()
{

person teacher;

teacher.year=2025;
strcpy(teacher.first,”Sam”);
strcpy(teacher.last,”Maggs”);

DisplayStats(teacher);
printf(“%s\n”,teacher.first);

return 0;
}

POINTERS Passing Values TO and FROM a Function

Address Label Label Address Value

teacher
teacher.first

teacher.first 400 – 431
Sam

teacher.last teacher.last 432 – 463 Maggs

teacher.year 464 – 467 2025

typedef struct human {
char first[32]; /* 1st field is array of char */
char last[32]; /* 2nd field is array of char */
int year; /* 3rd field is int */
} person; /* alias for human UDT ; */

int main()
{

person teacher, student;

teacher.year=2025;
strcpy(teacher.first,”Sam”);
strcpy(teacher.last,”Maggs”);

student = teacher;
PrintStructure(student);

UnChangeStruct(teacher);
ChangeStruct(&teacher);
PrintStructure(teacher);

return 0;
}

POINTERS Passing Values TO and FROM a Function

Address Label Label Address Value

teacher
teacher.first

teacher.first 400 – 431

teacher.last teacher.last 432 – 463

teacher.year 464 – 467
student
student.first

student.first 468 – 499

student.last student.last 500 – 531
student.year 532 – 535

5 6

7 8

typedef struct human {
char first[32]; /* 1st field is array of char */
char last[32]; /* 2nd field is array of char */
int year; /* 3rd field is int */
} person; /* alias for human UDT ; */

int main()
{

person teacher, student;

teacher.year=2025;
strcpy(teacher.first,”Sam”);
strcpy(teacher.last,”Maggs”);

student = teacher;
PrintStructure(student);

UnChangeStruct(teacher);
ChangeStruct(&teacher);
PrintStructure(teacher);

return 0;
}

POINTERS Passing Values TO and FROM a Function

Address Label Label Address Value

teacher
teacher.first

teacher.first 400 – 431
Sam

teacher.last teacher.last 432 – 463 Maggs

teacher.year 464 – 467 2025
student
student.first

student.first 468 – 499

student.last student.last 500 – 531
student.year 532 – 535

typedef struct human {
char first[32]; /* 1st field is array of char */
char last[32]; /* 2nd field is array of char */
int year; /* 3rd field is int */
} person; /* alias for human UDT ; */

int main()
{

person teacher, student;

teacher.year=2025;
strcpy(teacher.first,”Sam”);
strcpy(teacher.last,”Maggs”);

student = teacher;
PrintStructure(student);

UnChangeStruct(teacher);
ChangeStruct(&teacher);
PrintStructure(teacher);

return 0;
}

POINTERS Passing Values TO and FROM a Function

Address Label Label Address Value

teacher
teacher.first

teacher.first 400 – 431
Sam

teacher.last teacher.last 432 – 463 Maggs

teacher.year 464 – 467 2025
student
student.first

student.first 468 – 499
Sam

student.last student.last 500 – 531 Maggs
student.year 532 – 535 2025

typedef struct human {
char first[32]; /* 1st field is array of char */
char last[32]; /* 2nd field is array of char */
int year; /* 3rd field is int */
} person; /* alias for human UDT ; */

int main()
{

person teacher;

teacher.year=2025;
strcpy(teacher.first,”Sam”);
strcpy(teacher.last,”Maggs”);

UnChangeStruct(teacher);
ChangeStruct(&teacher);
PrintStructure(teacher);

return 0;
}

POINTERS Passing Values TO and FROM a Function

Address Label Label Address Value

teacher
teacher.first

teacher.first 400 – 431
Sam

teacher.last teacher.last 432 – 463 Maggs

teacher.year 464 – 467 2025

typedef struct human {
char first[32]; /* 1st field is array of char */
char last[32]; /* 2nd field is array of char */
int year; /* 3rd field is int */
} person; /* alias for human UDT ; */

int main()
{

person teacher;

teacher.year=2025;
strcpy(teacher.first,”Sam”);
strcpy(teacher.last,”Maggs”);

UnChangeStruct(teacher);
ChangeStruct(&teacher);
PrintStructure(teacher);

return 0;
}

POINTERS Passing Values TO and FROM a Function

Address Label Label Address Value

teacher
teacher.first

teacher.first 400 – 431
Sam

teacher.last teacher.last 432 – 463 Maggs

teacher.year 464 – 467 2025
inputStr
inputStr.first

inputStr.first 620 – 651
Ima

inputStr.last inputStr.last 652 – 683 Dunsl
inputStr.year 684 – 687

void UnChangeStruct( person inputStr)
{

strcpy(Input.first,”Ima”);
strcpy(Input.last,”Dunsl”);
PrintStructure(inputStr);

}

call frame (main)

9 10

11 12

typedef struct human {
char first[32]; /* 1st field is array of char */
char last[32]; /* 2nd field is array of char */
int year; /* 3rd field is int */
} person; /* alias for human UDT ; */

int main()
{

person teacher;

teacher.year=2025;
strcpy(teacher.first,”Sam”);
strcpy(teacher.last,”Maggs”);

UnChangeStruct(teacher);
ChangeStruct(&teacher);
PrintStructure(teacher);

// student = teacher;
// PrintStructure(student);

return 0;
}

POINTERS Passing Values TO and FROM a Function

Address Label Label Address Value

teacher
teacher.first

teacher.first 400 – 431
Sam

teacher.last teacher.last 432 – 463 Maggs

teacher.year 464 – 467 2025

typedef struct human {
char first[32]; /* 1st field is array of char */
char last[32]; /* 2nd field is array of char */
int year; /* 3rd field is int */
} person; /* alias for human UDT ; */

int main()
{

person teacher;

teacher.year=2025;
strcpy(teacher.first,”Sam”);
strcpy(teacher.last,”Maggs”);

UnChangeStruct(teacher);
ChangeStruct(&teacher);
PrintStructure(teacher);

// student = teacher;
// PrintStructure(student);

return 0;
}

POINTERS Passing Values TO and FROM a Function

Address Label Label Address Value

teacher
teacher.first

teacher.first 400 – 431
Sam

teacher.last teacher.last 432 – 463 Maggs

teacher.year 464 – 467 2025

refInputStr 640 – 643 400

void ChangeStruct( person *refInputStr)
{

strcpy(refInputStr.first,”Ima”);
strcpy(refInputStr.last,”Dunsl”);
refInputStr.year = 2042;
PrintStructure(refInputStr);

}

call frame (main)

Structures and Memory in C

END OF PART 1

DYNAMIC MEMORY ALLOCATION

– static memory allocation (non-changing)
– the size (in bytes) is known BEFORE

a program starts to execute
-when the program is loaded into memory,

allocation of declared variables is performed

– sometimes a program does not know exactly
how much memory it may need

i.e. reading a line of text – could be a character array of any size
– always declaring a humongous array very wasteful

– so: use dynamic memory allocation
ask the O/S to set aside x amount of memory during execution

POINTERS

13 14

15 16

DYNAMIC MEMORY ALLOCATION

variations on the malloc() function

notice malloc() requests exact number of bytes
– programmer must know how many based on how to be used

calloc() – sets aside cells (memory) and initializes all to zero

double *a;

a = (double *) calloc (70, 8);
70 x 8 bytes
70 double variables
560 byes

// could have used
a = (double *) calloc ( 70, sizeof(double) );

– same thing -> sizeof(?) returns size of variable type
based on O/S.

POINTERS

double *a; /* a pointer variable */
a = ( double *) malloc (40);

POINTERS

requesting O/S to set aside 40 bytes configured to handle values of type double
and assign the address of this memory block in the pointer variable a

NOTE: {DM} – is not a label
– just something to put in temporary symbol for allocated dynamic memory
(reserved memory for use later….)

requesting O/S to set aside 40 bytes configured to handle values of type double
and assign the address of this memory block in the pointer variable a

NOTE: {DM} – is not a label
– just something to put in temporary symbol for allocated dynamic memory
(reserved memory for use later….)

Label Address Value

a 400 – 403 10000

{DM} 10000 – 10039

typedef struct human {
char first[32]; /* 1st field is array of char */
char last[32]; /* 2nd field is array of char */
int year; /* 3rd field is int */
} person; /* alias for human UDT ; */

int main()
{

person *pTeacher;

pTeacher = (person *)calloc(1, sizeof(person));

pTeacher->year=2025;
strcpy(pTeacher->first,”Sam”);
strcpy(pTeacher->last,”Maggs”);

UnChangeStruct(*teacher);
ChangeStruct(teacher);
PrintStructure(teacher);

return 0;
}

POINTERS Passing Values TO and FROM a Function

Label Address Value

pTeacher 400 – 403 10000

{DM} 10000 – 10067

typedef struct human {
char first[32]; /* 1st field is array of char */
char last[32]; /* 2nd field is array of char */
int year; /* 3rd field is int */
} person; /* alias for human UDT ; */

int main()
{

person *pTeacher;

pTeacher = (person *)calloc(1, sizeof(person));

pTeacher->year=2025;
strcpy(pTeacher->first,”Sam”);
strcpy(pTeacher->last,”Maggs”);

UnChangeStruct(*teacher);
ChangeStruct(teacher);
PrintStructure(teacher);

return 0;
}

POINTERS Passing Values TO and FROM a Function

Label Address Value

pTeacher 400 – 403 10000

pTeacher->first 10000 – 10031 Sam
pTeacher->last 10032 – 10063 Maggs

pTeacher->year 10064 – 10067 2025

17 18

19 20

typedef struct human {
char first[32]; /* 1st field is array of char */
char last[32]; /* 2nd field is array of char */
int year; /* 3rd field is int */
} person; /* alias for human UDT ; */

int main()
{

person *pTeacher;

pTeacher = (person *)calloc(1, sizeof(person));

pTeacher->year=2025;
strcpy(pTeacher->first,”Sam”);
strcpy(pTeacher->last,”Maggs”);

UnChangeStruct(*pTeacher);
ChangeStruct(pTeacher);
PrintStructure(pTeacher);

return 0;
}

POINTERS Passing Values TO and FROM a Function

Label Address Value

pTeacher 400 – 403 10000

inputStr.first 640 – 671 Ima
inputStr.last 672 – 703 Dunsl
inputStr.year 704 – 707 2022

pTeacher->first 10000 – 10031 Sam
pTeacher->last 10032 – 10063 Maggs

pTeacher->year 10064 – 10067 2025

void UnChangeStruct( person inputStr)
{

strcpy(inputstr.first,”Ima”);
strcpy(inputstr.last,”Dunsl”);
inputstr.year = 2022;
PrintStructure(inputStr);

}

typedef struct human {
char first[32]; /* 1st field is array of char */
char last[32]; /* 2nd field is array of char */
int year; /* 3rd field is int */
} person; /* alias for human UDT ; */

int main()
{

person *pTeacher;

pTeacher = (person *)calloc(1, sizeof(person));

pTeacher->year=2025;
strcpy(pTeacher->first,”Sam”);
strcpy(pTeacher->last,”Maggs”);

UnChangeStruct(*pTeacher);
ChangeStruct(pTeacher);
PrintStructure(pTeacher);

return 0;
}

POINTERS Passing Values TO and FROM a Function

Label Address Value

pTeacher 400 – 403 10000

refInputStr 500 – 503 10000

pTeacher->first 10000 – 10031 Sam
pTeacher->last 10032 – 10063 Maggs

pTeacher->year 10064 – 10067 2025

void ChangeStruct( person *refInputStr)
{

strcpy(refInputStr->first,”Ima”);
strcpy(refInputStr->last,”Dunsl”);
// refInputStr->year = 2042;
PrintStructure(refInputStr);

}

typedef struct human {
char first[32]; /* 1st field is array of char */
char last[32]; /* 2nd field is array of char */
int year; /* 3rd field is int */
} person; /* alias for human UDT ; */

int main()
{

person *pTeacher;

pTeacher = (person *)calloc(1, sizeof(person));

pTeacher->year=2025;
strcpy(pTeacher->first,”Sam”);
strcpy(pTeacher->last,”Maggs”);

UnChangeStruct(*pTeacher);
ChangeStruct(pTeacher);
PrintStructure(pTeacher);

return 0;
}

POINTERS Passing Values TO and FROM a Function

Label Address Value

pTeacher 400 – 403 10000

refInputStr 500 – 503 10000

pTeacher->first 10000 – 10031 Ima
pTeacher->last 10032 – 10063 Dunsl

pTeacher->year 10064 – 10067 2025

void ChangeStruct( person *refInputStr)
{

strcpy(refInputStr->first,”Ima”);
strcpy(refInputStr->last,”Dunsl”);
// refInputStr->year = 2042;
PrintStructure(refInputStr);

}

typedef struct human {
char first[32]; /* 1st field is array of char */
char last[32]; /* 2nd field is array of char */
int year; /* 3rd field is int */
} person; /* alias for human UDT ; */

int main()
{

person *pTeacher;

pTeacher = (person *)calloc(1, sizeof(person));

pTeacher->year=2025;
strcpy(pTeacher->first,”Sam”);
strcpy(pTeacher->last,”Maggs”);

UnChangeStruct(*pTeacher);
ChangeStruct(pTeacher);
PrintStructure(pTeacher);

return 0;
}

POINTERS Passing Values TO and FROM a Function

Label Address Value

pTeacher 400 – 403 10000

pTeacher->first 10000 – 10031 Ima
pTeacher->last 10032 – 10063 Dunsl

pTeacher->year 10064 – 10067 2025

21 22

23 24

typedef struct human {
char first[32]; /* 1st field is array of char */
char last[32]; /* 2nd field is array of char */
int year; /* 3rd field is int */
} person; /* alias for human UDT ; */

int main()
{

person *pTeacher;

pTeacher = (person *)calloc(4, sizeof(person));

pTeacher[2].year=2025;
strcpy(pTeacher[2].first,”Sam”);
strcpy(pTeacher[2].last,”Maggs”);

UnChangeStruct(pTeacher[2]);
ChangeStruct(&pTeacher[2]);
PrintStructure(pTeacher[2]););

return 0;
}

POINTERS Passing Values TO and FROM a Function

Label Address Value

pTeacher 400 – 403 10000

{DM} 10000 – 10271

typedef struct human {
char first[32]; /* 1st field is array of char */
char last[32]; /* 2nd field is array of char */
int year; /* 3rd field is int */
} person; /* alias for human UDT ; */

int main()
{

person *pTeacher;

pTeacher = (person *)calloc(4, sizeof(person));

pTeacher[2].year=2025;
strcpy(pTeacher[2].first,”Sam”);
strcpy(pTeacher[2].last,”Maggs”);

UnChangeStruct(pTeacher[2]);
ChangeStruct(&pTeacher[2]);
PrintStructure(pTeacher[2]););

return 0;
}

POINTERS Passing Values TO and FROM a Function

Label Address Value

pTeacher 400 – 403 10000

{DM} 10000 – 10135
pTeacher[2].first 10136 – 10167 Sam
pTeacher[2].last 10168 – 10199 Maggs

pTeacher[2].year 10200 – 10203 2025
{DM} 10204 – 10271

typedef struct human {
char first[32]; /* 1st field is array of char */
char last[32]; /* 2nd field is array of char */
int year; /* 3rd field is int */
} person; /* alias for human UDT ; */

int main()
{

person *pTeacher;

pTeacher = (person *)calloc(4, sizeof(person));

pTeacher[2].year=2025;
strcpy(pTeacher[2].first,”Sam”);
strcpy(pTeacher[2].last,”Maggs”);

UnChangeStruct(pTeacher[2]);
ChangeStruct(&pTeacher[2]);
PrintStructure(pTeacher[2]););

return 0;
}

POINTERS Passing Values TO and FROM a Function

Label Address Value

pTeacher 400 – 403 10000

inputStr.first 640 – 671 Ima
inputStr.last 672 – 703 Dunsl
inputStr.year 704 – 707 2022

{DM} 10000 – 10135
pTeacher[2].first 10136 – 10167 Sam
pTeacher[2].last 10168 – 10199 Maggs

pTeacher[2].year 10200 – 10203 2025
{DM} 10204 – 10271

void UnChangeStruct( person inputStr)
{

strcpy(inputstr.first,”Ima”);
strcpy(inputstr.last,”Dunsl”);
inputstr.year = 2022;
PrintStructure(inputStr);

}

typedef struct human {
char first[32]; /* 1st field is array of char */
char last[32]; /* 2nd field is array of char */
int year; /* 3rd field is int */
} person; /* alias for human UDT ; */

int main()
{

person *pTeacher;

pTeacher = (person *)calloc(4, sizeof(person));

pTeacher[2].year=2025;
strcpy(pTeacher[2].first,”Sam”);
strcpy(pTeacher[2].last,”Maggs”);

UnChangeStruct(pTeacher[2]);
ChangeStruct(&pTeacher[2]);
PrintStructure(pTeacher[2]););

return 0;
}

POINTERS Passing Values TO and FROM a Function

Label Address Value

pTeacher 400 – 403 10000

refInputStr 500 – 503 10136

{DM} 10000 – 10135
pTeacher[2].first 10136 – 10167 Sam
pTeacher[2].last 10168 – 10199 Maggs

pTeacher[2].year 10200 – 10203 2025
{DM} 10204 – 10271

void ChangeStruct( person *refInputStr)
{

strcpy(refInputStr->first,”Ima”);
strcpy(refInputStr->last,”Dunsl”);
// refInputStr->year = 2042;
PrintStructure(refInputStr);

}

25 26

27 28

typedef struct human {
char first[32]; /* 1st field is array of char */
char last[32]; /* 2nd field is array of char */
int year; /* 3rd field is int */
} person; /* alias for human UDT ; */

int main()
{

person *pTeacher;

pTeacher = (person *)calloc(4, sizeof(person));

pTeacher[2].year=2025;
strcpy(pTeacher[2].first,”Sam”);
strcpy(pTeacher[2].last,”Maggs”);

UnChangeStruct(pTeacher[2]);
ChangeStruct(&pTeacher[2]);
PrintStructure(pTeacher[2]););

return 0;
}

POINTERS Passing Values TO and FROM a Function

Label Address Value

pTeacher 400 – 403 10000

refInputStr 500 – 503 10136

{DM} 10000 – 10135
pTeacher[2].first 10136 – 10167 Ima
pTeacher[2].last 10168 – 10199 Dunsl

pTeacher[2].year 10200 – 10203 2025
{DM} 10204 – 10271

void ChangeStruct( person *refInputStr)
{

strcpy(refInputStr->first,”Ima”);
strcpy(refInputStr->last,”Dunsl”);
// refInputStr->year = 2042;
PrintStructure(refInputStr);

}

Structures and Memory in C

END OF PART 2

double *a; /* a pointer variable */
a = ( double *) malloc (40);

/* can just assume the malloc(40) call set aside
an area in the heap to accommodate 5 double variables
(40 bytes is:

8 bytes (size of a double variable) x 5 )
so, the virtual labels immediately available for use )

POINTERS

Label Address Value

a 400 – 403 10000

*(a+0) a[0] 10000 – 10007
*(a+1) a[1] 10008 – 10015
*(a+2) a[2] 10016 – 10023
*(a+3) a[3] 10024 – 10031
*(a+4) a[4] 10032 – 10039

double *a; /* a pointer variable */
a = ( double *) malloc (40);
A[0] = 37;
A[2] = 64;
…
// BUT! What if five elements was not enough !

POINTERS

Label Address Value

a 400 – 403 10000

*(a+0) a[0] 10000 – 10007 37
*(a+1) a[1] 10008 – 10015
*(a+2) a[2] 10016 – 10023 64
*(a+3) a[3] 10024 – 10031
*(a+4) a[4] 10032 – 10039

29 30

31 32

DYNAMIC MEMORY ALLOCATION

variations on the malloc() function

notice malloc() requests exact number of bytes
– programmer must know how many based on how to be used

realloc() – is used to resize allocated memory without losing existing data

double *a;
a = (double *)malloc(5 *sizeof(double));

a = (double *) realloc (a, 9*sizeof(double));
9 x 8 bytes
increase to 9 double variables
72 byes

// could have used
a = (double *) realloc (a, 3*sizeof(double));

– decrease to 3 double variables
24 bytes.

POINTERS

double *a; /* a pointer variable */
a = ( double *) malloc (40);
A[0] = 37;
A[2] = 64;
…
// BUT! What if five elements was not enough !

POINTERS

Label Address Value

a 400 – 403 10000

{DM} 10000 – 10039

double *a; /* a pointer variable */
a = ( double *) malloc (40);
A[0] = 37;
A[2] = 64;
…
// BUT! What if five elements was not enough !

POINTERS

Label Address Value

a 400 – 403 10000

*(a+0) a[0] 10000 – 10007 37
*(a+1) a[1] 10008 – 10015
*(a+2) a[2] 10016 – 10023 64
*(a+3) a[3] 10024 – 10031
*(a+4) a[4] 10032 – 10039

double *a; /* a pointer variable */
a = ( double *) malloc (40);
A[0] = 37;
A[2] = 64;
…
// BUT! What if five elements was not enough !
a = realloc ( a, 7 * sizeof(double) );

POINTERS

Label Address Value

a 400 – 403 10000

{DM} 10000 – 10039

33 34

35 36

double *a; /* a pointer variable */
a = ( double *) malloc (40);
A[0] = 37;
A[2] = 64;
…
// BUT! What if five elements was not enough !
a = realloc ( a, 7 * sizeof(double) );

POINTERS

Label Address Value

a 400 – 403 10000

{DM} 10000 – 10055

double *a; /* a pointer variable */
a = ( double *) malloc (40);
A[0] = 37;
A[2] = 64;
…
// BUT! What if five elements was not enough !
a = realloc ( a, 7 * sizeof(double) );

POINTERS

Label Address Value

a 400 – 403 10000

*(a+0) a[0] 10000 – 10007 37
*(a+1) a[1] 10008 – 10015
*(a+2) a[2] 10016 – 10023 64
*(a+3) a[3] 10024 – 10031
*(a+4) a[4] 10032 – 10039
*(a+5) a[5] 10040 – 10047
*(a+6) a[6] 10048 – 10055

double *a; /* a pointer variable */
a = ( double *) malloc (40);
A[0] = 37;
A[2] = 64;
…
// BUT! What if five elements was not enough !
a = realloc ( a, 7 * sizeof(double) );

POINTERS

Label Address Value

a 400 – 403 10000

1st case: If sufficient memory is available after address 10039,
then the address of a doesn’t change.
1st case: If sufficient memory is available after address 10039,
then the address of a doesn’t change.

2nd case: If sufficient memory is not available after address 10039,
then the realloc() function allocates memory somewhere else in the
heap and copies the all content from old memory block to the new

memory block.
In this case the address of a changes.

Structures and Memory in C

END OF PART 3

37 38

39 40

int i; /* an integer variable */
int *ptr1_i; /* a pointer variable that points to i */
int **ptr2_i; /* a pointer variable that points to i */
int x; /* another integer variable */

i = 37;
ptr1_i = &i;
ptr2_i = &ptr1_i;
x = **ptr2_i;

Label Address Value

i 400 – 403 37
ptr1_i 404 – 407 400
ptr2_i 408 – 411 404

x 412 – 415 37

POINTERS (double pointers) POINTERS Passing Values TO and FROM a Function

#include

int twoDimArray(int **passedArray)
{

printf(“address of passedArray[0]: %u\n”, &passedArray[0]);
printf(“address of passedArray[1]: %u\n”, &passedArray[1]);
passedArray [0][1] = 56;
*(*(passedArray+1)+0) = -31; /* same as passedArray [1][0] */

}

int main(int argc, char *argv[])
{

int **m; /* 4 bytes (just an address) */
m = (int **) calloc (2, sizeof(int *) ); /* 2 x 4 bytes */
m[0] = (int *) calloc ( 3, sizeof(int)); /* 3 x 4 bytes */
m[1] = (int *) calloc ( 2, sizeof(int)); /* 2 x 4 bytes */
printf(“address of m[0]: %u\n”, &m[0]);
printf(“address of m[1]: %u\n”, &m[1]);

twoDimArray(m);

printf(“value of m[0][1]: %d \n”,m[0][1]);
printf(“value of m[1][0]: %d \n”,m[1][0]);

}

int **m; /* 4 bytes (just an address) */
m = (int **) calloc (2, sizeof(int *) ); /* 2 x 4 bytes */
m[0] = (int *) calloc ( 3, sizeof(int)); /* 3 x 4 bytes */
m[1] = (int *) calloc ( 2, sizeof(int)); /* 2 x 4 bytes */
m[0][1] = 56;
*(*(m+1)+0) = -31; /* same as m[1][0] – either okay */

POINTERS (double pointers)

Label Address Value

m 400 – 404 10100

{DM} 10100 – 10107
{DM} 10108 – 10119
{DM} 10120 – 10127

Label Address Value

m 400 – 404 10100

*(m+0) m[0] 10100 – 10103 10108
*(m+1) m[1] 10104 – 10107 10120
*(*(m+0)+0) m[0][0] 10108 – 10111
*(*(m+0)+1) m[0][1] 10112 – 10115 56
*(*(m+0)+2) m[0][2] 10116 – 10119
*(*(m+1)+0) m[1][0] 10120 – 10123 -31
*(*(m+1)+1) m[1][1] 10124 – 10127

POINTERS Passing Values TO and FROM a Function

#include

int twoDimArray(int **passedArray)
{

}

int main(int argc, char *argv[])
{

twoDimArray(m);

printf(“value of m[0][1]: %d \n”,m[0][1]);
printf(“value of m[1][0]: %d \n”,m[1][0]);

}

Label Address Value

m 400 – 404 10100

41 42

43 44

typedef struct human {
char first[32]; /* 1st field is array of char */
char last[32]; /* 2nd field is array of char */
int year; /* 3rd field is int */
} person; /* alias for human UDT ; */

int main()
{

person **dpTeacher;

dpTeacher = (person **)calloc(1, sizeof(person *));

addTeacher(dpTeacher);
printTeacher(dpTeacher);

strcpy(dpTeacher[0][0].first,”Bob”);
strcpy( (*dpTeacher)[0].first,“Ted”);

(*(dpTeacher+0)+2)->year = 5;

return 0;
}

POINTERS Passing Values TO and FROM a Function

typedef struct human {
char first[32]; /* 1st field is array of char */
char last[32]; /* 2nd field is array of char */
int year; /* 3rd field is int */
} person; /* alias for human UDT ; */

int main()
{

person **dpTeacher;

dpTeacher = (person **)calloc(1, sizeof(person *));

addTeacher(dpTeacher);
printTeacher(dpTeacher);

strcpy(dpTeacher[0][0].first,”Bob”);
strcpy( (*dpTeacher)[0].first,“Ted”);

(*(dpTeacher+0)+2)->year = 5;

return 0;
}

POINTERS Passing Values TO and FROM a Function

Label Address Value

dpTeacher 400 – 403

typedef struct human {
char first[32]; /* 1st field is array of char */
char last[32]; /* 2nd field is array of char */
int year; /* 3rd field is int */
} person; /* alias for human UDT ; */

int main()
{

person **dpTeacher;

dpTeacher = (person **)calloc(1, sizeof(person *));

addTeacher(dpTeacher);
printTeacher(dpTeacher);

strcpy(dpTeacher[0][0].first,”Bob”);
strcpy( (*dpTeacher)[0].first,“Ted”);

(*(dpTeacher+0)+2)->year = 5;

return 0;
}

POINTERS Passing Values TO and FROM a Function

Label Address Value

dpTeacher 400 – 403 10000

{DM} 10000 – 10003

typedef struct human {
char first[32]; /* 1st field is array of char */
char last[32]; /* 2nd field is array of char */
int year; /* 3rd field is int */
} person; /* alias for human UDT ; */

int main()
{

person **dpTeacher;

dpTeacher = (person **)calloc(1, sizeof(person *));

addTeacher(dpTeacher);
printTeacher(dpTeacher);

strcpy(dpTeacher[0][0].first,”Bob”);
strcpy( (*dpTeacher)[0].first,“Ted”);

(*(dpTeacher+0)+2)->year = 5;

return 0;
}

POINTERS Passing Values TO and FROM a Function

Label Address Value

dpTeacher 400 – 403 10000

dpT 510 – 413 10000

{DM} 10000 – 10003

void addTeacher(person **dpT){

dpT[0] = (person *) calloc ( 5, sizeof(person)); /* 5 x 68 bytes */
for (int i=0; i<5; i++){ strcpy( (*dpT)[i].first,"Sam"); strcpy( (*dpT)[i].last,"Maggs"); (*dpT)[i].year = 2042; } } 45 46 47 48 13 typedef struct human { char first[32]; /* 1st field is array of char */ char last[32]; /* 2nd field is array of char */ int year; /* 3rd field is int */ } person; /* alias for human UDT ; */ int main() { person **dpTeacher; dpTeacher = (person **)calloc(1, sizeof(person *)); addTeacher(dpTeacher); printTeacher(dpTeacher); strcpy(dpTeacher[0][0].first,"Bob"); strcpy( (*dpTeacher)[0].first,“Ted"); (*(dpTeacher+0)+2)->year = 5;

return 0;
}

POINTERS Passing Values TO and FROM a Function

Label Address Value

dpTeacher 400 – 403 10000

dpT 510 – 413 10000

{DM} 10000 – 10003 10140
{DM} 10140 – 10479

void addTeacher(person **dpT){

*dpT = (person *) calloc ( 5, sizeof(person)); /* 5 x 68 bytes */
// dpT[0] = (person *) calloc ( 5, sizeof(person));
for (int i=0; i<5; i++){ strcpy( (*dpT)[i].first,"Sam"); strcpy( (*dpT)[i].last,"Maggs"); (*dpT)[i].year = 2042; } } typedef struct human { char first[32]; /* 1st field is array of char */ char last[32]; /* 2nd field is array of char */ int year; /* 3rd field is int */ } person; /* alias for human UDT ; */ int main() { person **dpTeacher; dpTeacher = (person **)calloc(1, sizeof(person *)); addTeacher(dpTeacher); printTeacher(dpTeacher); strcpy(dpTeacher[0][0].first,"Bob"); strcpy( (*dpTeacher)[0].first,“Ted"); (*(dpTeacher+0)+2)->year = 5;

return 0;
}

POINTERS Passing Values TO and FROM a Function

Label Address Value

dpTeacher 400 – 403 10000

dpT 510 – 413 10000

dpT[0] 10000 – 10003 10140
{DM} 10140 – 10479

void addTeacher(person **dpT){

dpT[0] = (person *) calloc ( 5, sizeof(person)); /* 5 x 68 bytes */
for (int i=0; i<5; i++){ strcpy( (*dpT)[i].first,"Sam"); strcpy( (*dpT)[i].last,"Maggs"); (*dpT)[i].year = 2042; } } typedef struct human { char first[32]; /* 1st field is array of char */ char last[32]; /* 2nd field is array of char */ int year; /* 3rd field is int */ } person; /* alias for human UDT ; */ int main() { person **dpTeacher; dpTeacher = (person **)calloc(1, sizeof(person *)); addTeacher(dpTeacher); printTeacher(dpTeacher); strcpy(dpTeacher[0][0].first,"Bob"); strcpy( (*dpTeacher)[0].first,“Ted"); (*(dpTeacher+0)+2)->year = 5;

return 0;
}

POINTERS Passing Values TO and FROM a Function

Label Address Value

dpTeacher 400 – 403 10000

dpT 510 – 413 10000

dpt[0] 10000 – 10003 10140
dpt[0][0].first 10140 – 10171 Sam
dpt [0][0].last 10172 – 10203 Maggs

dpt[0][0].year 10204 – 10207 2042
dpt[0][1].first 10208 – 10239 Sam

{DM} 10240 – 10271

void addTeacher(person **dpT){

dpT[0] = (person *) calloc ( 5, sizeof(person)); /* 5 x 68 bytes */
for (int i=0; i<5; i++){ strcpy( (*dpT)[i].first,"Sam"); strcpy( (*dpT)[i].last, "Maggs"); (*dpT)[i].year = 2042; } } typedef struct human { char first[32]; /* 1st field is array of char */ char last[32]; /* 2nd field is array of char */ int year; /* 3rd field is int */ } person; /* alias for human UDT ; */ int main() { person **dpTeacher; dpTeacher = (person **)calloc(1, sizeof(person *)); addTeacher(dpTeacher); printTeacher(dpTeacher); strcpy(dpTeacher[0][0].first,"Bob"); strcpy( (*dpTeacher)[0].first,“Ted"); (*(dpTeacher+0)+2)->year = 5;

return 0;
}

POINTERS Passing Values TO and FROM a Function

Label Address Value

dpTeacher 400 – 403 10000

dpT 510 – 413 10000

*dpt 10000 – 10003 10140
*dpt[0].first 10140 – 10171 Sam
*dpt [0].last 10172 – 10203 Maggs

*dpt[0].year 10204 – 10207 2042
*dpt[1].first 10208 – 10239 Sam

{DM} 10240 – 10271

void addTeacher(person **dpT){

dpT[0] = (person *) calloc ( 5, sizeof(person)); /* 5 x 68 bytes */
for (int i=0; i<5; i++){ strcpy( (*dpT)[i].first,"Sam"); strcpy( (*dpT)[i].last, "Maggs"); (*dpT)[i].year = 2042; } } 49 50 51 52 14 typedef struct human { char first[32]; /* 1st field is array of char */ char last[32]; /* 2nd field is array of char */ int year; /* 3rd field is int */ } person; /* alias for human UDT ; */ int main() { person **dpTeacher; dpTeacher = (person **)calloc(1, sizeof(person *)); addTeacher(dpTeacher); printTeacher(dpTeacher); strcpy(dpTeacher[0][0].first,"Bob"); strcpy( (*dpTeacher)[0].first,“Ted"); (*(dpTeacher+0)+2)->year = 5;

return 0;
}

POINTERS Passing Values TO and FROM a Function

Label Address Value

dpTeacher 400 – 403 10000

*dpt 10000 – 10003 10140
*dpt[0].first 10140 – 10171 Sam
*dpt [0].last 10172 – 10203 Maggs

*dpt[0].year 10204 – 10207 2042
*dpt[1].first 10208 – 10239 Sam

{DM} 10240 – 10271

typedef struct human {
char first[32]; /* 1st field is array of char */
char last[32]; /* 2nd field is array of char */
int year; /* 3rd field is int */
} person; /* alias for human UDT ; */

int main()
{

person **dpTeacher;

dpTeacher = (person **)calloc(1, sizeof(person *));

addTeacher(dpTeacher);
printTeacher(dpTeacher);

strcpy(dpTeacher[0][0].first,”Bob”);
strcpy( (*dpTeacher)[0].first,“Ted”);

(*(dpTeacher+0)+2)->year = 5;

return 0;
}

POINTERS Passing Values TO and FROM a Function

Label Address Value

dpTeacher 400 – 403 10000

dpT 620 – 623 10000

*dpt 10000 – 10003 10140
*dpt[0].first 10140 – 10171 Sam
*dpt [0].last 10172 – 10203 Maggs

*dpt[0].year 10204 – 10207 2042
*dpt[1].first 10208 – 10239 Sam

{DM} 10240 – 10271

void printTeacher(person **dpT){

printf(“\nThis is the contents of the dynamically allocated:\n”);
for (int i=1;i<=3;i++){ printf("Teacher %s ",(*dpT)[i].first); printf("%s ",dpT[0][i].last); printf("%d\n\n",(*(dpT+0)+i)->year);

}
}

typedef struct human {
char first[32]; /* 1st field is array of char */
char last[32]; /* 2nd field is array of char */
int year; /* 3rd field is int */
} person; /* alias for human UDT ; */

int main()
{

person **dpTeacher;

dpTeacher = (person **)calloc(1, sizeof(person *));

addTeacher(dpTeacher);
printTeacher(dpTeacher);

strcpy(dpTeacher[0][0].first,”Bob”);
strcpy( (*dpTeacher)[0].first,“Ted”);

(*(dpTeacher+0)+2)->year = 5;

return 0;
}

POINTERS Passing Values TO and FROM a Function

Label Address Value

dpTeacher 400 – 403 10000

dpT 620 – 623 10000

*dpt 10000 – 10003 10140
*dpt[0].first 10140 – 10171 Sam
*dpt [0].last 10172 – 10203 Maggs

*dpt[0].year 10204 – 10207 2042
*dpt[1].first 10208 – 10239 Sam

{DM} 10240 – 10271

void printTeacher(person **dpT){

printf(“\nThis is the contents of the dynamically allocated:\n”);
for (int i=1;i<=3;i++){ printf("Teacher %s ",(*dpT)[i].first); printf("%s ",dpT[0][i].last); printf("%d\n\n",(*(dpT+0)+i)->year);

}
}

typedef struct human {
char first[32]; /* 1st field is array of char */
char last[32]; /* 2nd field is array of char */
int year; /* 3rd field is int */
} person; /* alias for human UDT ; */

int main()
{

person **dpTeacher;

dpTeacher = (person **)calloc(1, sizeof(person *));

addTeacher(dpTeacher);
printTeacher(dpTeacher);

strcpy(dpTeacher[0][0].first,”Bob”);
strcpy( (*dpTeacher)[0].first,“Ted”);

(*(dpTeacher+0)+2)->year = 5;

return 0;
}

POINTERS Passing Values TO and FROM a Function

Label Address Value

dpTeacher 400 – 403 10000

dpT 620 – 623 10000

*dpt 10000 – 10003 10140
*dpt[0].first 10140 – 10171 Sam

dpt [0][1].last 10172 – 10203 Maggs
*dpt[0].year 10204 – 10207 2042
*dpt[1].first 10208 – 10239 Sam

{DM} 10240 – 10271

void printTeacher(person **dpT){

printf(“\nThis is the contents of the dynamically allocated:\n”);
for (int i=1;i<=3;i++){ printf("Teacher %s ",(*dpT)[i].first); printf("%s ",dpT[0][i].last); printf("%d\n\n",(*(dpT+0)+i)->year);

}
}

53 54

55 56

typedef struct human {
char first[32]; /* 1st field is array of char */
char last[32]; /* 2nd field is array of char */
int year; /* 3rd field is int */
} person; /* alias for human UDT ; */

int main()
{

person **dpTeacher;

dpTeacher = (person **)calloc(1, sizeof(person *));

addTeacher(dpTeacher);
printTeacher(dpTeacher);

strcpy(dpTeacher[0][0].first,”Bob”);
strcpy( (*dpTeacher)[0].first,“Ted”);

(*(dpTeacher+0)+2)->year = 5;

return 0;
}

POINTERS Passing Values TO and FROM a Function

Label Address Value

dpTeacher 400 – 403 10000

dpT 620 – 623 10000

*dpt 10000 – 10003 10140
*dpt[0].first 10140 – 10171 Sam
*dpt [0].last 10172 – 10203 Maggs

(*(dpT+0)+1)year 10204 – 10207 2042
*dpt[1].first 10208 – 10239 Sam

{DM} 10240 – 10271

void printTeacher(person **dpT){

printf(“\nThis is the contents of the dynamically allocated:\n”);
for (int i=1;i<=3;i++){ printf("Teacher %s ",(*dpT)[i].first); printf("%s ",dpT[0][i].last); printf("%d\n\n",(*(dpT+0)+i)->year);

}
}

typedef struct human {
char first[32]; /* 1st field is array of char */
char last[32]; /* 2nd field is array of char */
int year; /* 3rd field is int */
} person; /* alias for human UDT ; */

int main()
{

person **dpTeacher;

dpTeacher = (person **)calloc(1, sizeof(person *));

addTeacher(dpTeacher);
printTeacher(dpTeacher);

strcpy(dpTeacher[0][0].first,”Bob”);
strcpy( (*dpTeacher)[0].first,“Ted”);

(*(dpTeacher+0)+2)->year = 5;

return 0;
}

POINTERS Passing Values TO and FROM a Function

Label Address Value

dpTeacher 400 – 403 10000

*dpt 10000 – 10003 10140
*dpt[0].first 10140 – 10171 Sam
*dpt [0].last 10172 – 10203 Maggs

*dpt[0].year 10204 – 10207 2042
*dpt[1].first 10208 – 10239 Sam

{DM} 10240 – 10271

typedef struct human {
char first[32]; /* 1st field is array of char */
char last[32]; /* 2nd field is array of char */
int year; /* 3rd field is int */
} person; /* alias for human UDT ; */

int main()
{

person **dpTeacher;

dpTeacher = (person **)calloc(1, sizeof(person *));

addTeacher(dpTeacher);
printTeacher(dpTeacher);

strcpy(dpTeacher[0][0].first,”Bob”);
strcpy( (*dpTeacher)[0].first,“Ted”);

(*(dpTeacher+0)+2)->year = 5;

return 0;
}

POINTERS Passing Values TO and FROM a Function

Label Address Value

dpTeacher 400 – 403 10000

{DM} 10000 – 10003 10140
{DM} 10140 – 10271 *****

typedef struct human {
char first[32]; /* 1st field is array of char */
char last[32]; /* 2nd field is array of char */
int year; /* 3rd field is int */
} person; /* alias for human UDT ; */

int main()
{

person **dpTeacher;

dpTeacher = (person **)calloc(1, sizeof(person));

addTeacher(dpTeacher);
printTeacher(dpTeacher);

strcpy(dpTeacher[0][0].first,”Bob”);
strcpy( (*dpTeacher)[0].first,“Ted”);

(*(dpTeacher+0)+2)->year = 5;

return 0;
}

POINTERS Passing Values TO and FROM a FunctionLabel Address Value

dpTeacher 400 – 403 10000

dpTeacher[0] 10000 – 10003 10140
dpTeacher[0][0].first 10140 – 10171 Bob
dpTeacher[0][0].last 10172 – 10203 Maggs

dpTeacher[0][0].year 10204 – 10207 2042
dpTeacher[0][1].first 10208 – 10239 Sam

{DM} 10240 – 10271

57 58

59 60

typedef struct human {
char first[32]; /* 1st field is array of char */
char last[32]; /* 2nd field is array of char */
int year; /* 3rd field is int */
} person; /* alias for human UDT ; */

int main()
{

person **dpTeacher;

dpTeacher = (person **)calloc(1, sizeof(person));

addTeacher(dpTeacher);
printTeacher(dpTeacher);

strcpy(dpTeacher[0][0].first,”Bob”);
strcpy( (*dpTeacher)[0].first,“Ted”);

(*(dpTeacher+0)+2)->year = 5;

return 0;
}

POINTERS Passing Values TO and FROM a FunctionLabel Address Value

dpTeacher 400 – 403 10000

*dpTeacher 10000 – 10003 10140
*dpTeacher[0].first 10140 – 10171 Bob
*dpTeacher[0].last 10172 – 10203 Maggs

*dpTeacher[0].year 10204 – 10207 2042
*dpTeacher[1].first 10208 – 10239 Sam

{DM} 10240 – 10271

typedef struct human {
char first[32]; /* 1st field is array of char */
char last[32]; /* 2nd field is array of char */
int year; /* 3rd field is int */
} person; /* alias for human UDT ; */

int main()
{

person **dpTeacher;

dpTeacher = (person **)calloc(1, sizeof(person));

addTeacher(dpTeacher);
printTeacher(dpTeacher);

strcpy(dpTeacher[0][0].first,”Bob”);
strcpy( (*dpTeacher)[0].first,”Ted”);

(*(dpTeacher+0)+2)->year = 5;

return 0;
}

POINTERS Passing Values TO and FROM a FunctionLabel Address Value

dpTeacher 400 – 403 10000

*(dpTeacher+0) 10000 – 10003 10140
(*(dpTeacher+0)+0) ->first 10140 – 10171 Bob
(*(dpTeacher+0)+1)->last 10172 – 10203 Maggs

(*(dpTeacher+0)+2)->year 10204 – 10207 2042
(*(dpTeacher+1)+0)->first 10208 – 10239 Sam

{DM} 10240 – 10271

typedef struct human {
char first[32]; /* 1st field is array of char */
char last[32]; /* 2nd field is array of char */
int year; /* 3rd field is int */
} person; /* alias for human UDT ; */

int main()
{

person **dpTeacher;

dpTeacher = (person **)calloc(1, sizeof(person *));

addTeacher(dpTeacher);
printTeacher(dpTeacher);

strcpy(dpTeacher[0][0].first,”Bob”);
strcpy( (*dpTeacher)[0].first,”Ted”);

(*(dpTeacher+0)+2)->year = 5;

return 0;
}

POINTERS Passing Values TO and FROM a Function

typedef struct human {
char first[32]; /* 1st field is array of char */
char last[32]; /* 2nd field is array of char */
int year; /* 3rd field is int */
} person; /* alias for human UDT ; */

int main()
{

person **dpTeacher;

dpTeacher = (person **)calloc(3, sizeof(person *));
dpTeacher[0] = (person *) calloc ( 5, sizeof(person)); /* 5 x 68 bytes */
dpTeacher[1] = (person *) calloc ( 5, sizeof(person)); /* 5 x 68 bytes */
dpTeacher[2] = (person *) calloc ( 5, sizeof(person)); /* 5 x 68 bytes */

addTeacher(dpTeacher); /* print a part or the whole matrix */
printTeacher(dpTeacher[1]); /* print an entire row */

strcpy(dpTeacher[2][3].first,”Bob”);
strcpy( (*dpTeacher+2)[0].first,”Ted”);

(*(dpTeacher+1)+2)->year = 5;

return 0;
}

POINTERS Passing Values TO and FROM a Function

61 62

63 64

typedef struct human {
char first[32]; /* 1st field is array of char */
char last[32]; /* 2nd field is array of char */
int year; /* 3rd field is int */
} person; /* alias for human UDT ; */

int main()
{

person **dpTeacher;

addTeacher(dpTeacher); /* print a part or the whole matrix */
printTeacher(dpTeacher[1]); /* print an entire row */

strcpy(dpTeacher[2][3].first,”Bob”);
strcpy( (*dpTeacher+2)[0].first,”Ted”);

(*(dpTeacher+1)+2)->year = 5;

return 0;
}

POINTERS Passing Values TO and FROM a Function

Label Address Value

dpTeacher 400 – 403 10000

{DM} 10000 – 10011 10140
{DM} 10140 – 10479 *****
{DM} 10200 – 10539 *****
{DM} 10540 – 10879 *****

Double Pointers

END OF PART 4

65 66

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