Question

I have the following code. The interesting part is if I uncomment the resize() on vector, it is priting 10 numbers for an input value of 5. I am using eclipse with mingw and gcc on windows xp. Shouldn’t the iterator go only for 5 elements?

#include <iostream>
#include <string>
#include <vector>
#include <map>
#include <set>
#include <algorithm>
//#include "stdio.h"
using namespace std;

template <typename T>
void print_coll(T t)
{
    typename T::iterator iter = t.begin();
    while (iter != t.end() )
    {
        cout << *iter << " ";
        ++iter;
    }
    cout << endl;
}

int main()
{
    int size;
    cin >> size;
    vector<int> numbers;
//    numbers.resize(size);

    for ( int i = 0 ; i < size; ++i ) {
        int r = (rand() % 10);
        numbers.push_back(r);
    }
    print_coll(numbers);

}

Answer 1

resize resizes the vector, inserting default values for each of the items it needs to create for the new size. You want reserve.