CS计算机代考程序代写 // Map.cpp

using namespace std;

//——————————————————
// typedefs make it easier to use the various types.
typedef map Popularity;
typedef Popularity::iterator PopItr;
typedef Popularity::const_iterator cPopItr; // when is this going to be used?

//——————————————————
//Forward declarations as main() is at the top of the source code file
void AddData (Popularity &pop);
void Output (const Popularity &pop); // should it be the version below?
//void Output (Popularity &pop);

//——————————————————

int main ()
{
Popularity pop;

AddData (pop);
Output (pop);

cout << endl; return 0; } //------------------------------------------------------ void AddData (Popularity &pop) { string name; // Prime the while loop cout << "Enter vote name, or 'end' to finish: "; getline (cin, name, '\n'); while (name != "end") // how much processing is needed just to make this comparison? // name is std:string and "end" is a C string { // If this person is not yet in the map if (pop.find(name) == pop.end()) { // Add them to the map pop[name] = 1; } else { // Otherwise just increment the number of votes in the map pop[name]++; } cout << "Enter vote name, or 'end' to finish: "; getline (cin, name); } } //------------------------------------------------------ void Output (const Popularity &pop) // should it the version as in the commented code below? why? //void Output (Popularity &pop) { cPopItr winner = pop.begin(); // should it be the version below? why? //PopItr winner = pop.begin(); // For each entry in the map for (cPopItr itr = pop.begin(); itr != pop.end(); itr++) //for (PopItr itr = pop.begin(); itr != pop.end(); itr++) // why not this one? { // Output the first and second parts of the pair (association) cout << setw(20) << itr->first << ": " << itr->second << endl; // Now check if this person should be the winner if (winner->second < itr->second)
{
winner = itr;
}
}

// Output the winner.
if (pop.begin() != pop.end()) // why???
{
cout << endl << "The new class president is " << winner->first
<< " with " << winner->second << " votes" << endl; // what if the votes are equal? } else { cout << "no data" << endl; } } //------------------------------------------------------