c++ make vector loop more faster
#include <vector>
#include <iostream>
#include <ctime>
using namespace std;
int main() {
const int BIG = 20000000;
vector <int> v;
for ( int i = 0; i < BIG; i++ ) {
v.push_back( i );
}
int now = time(0);
cout << "start" << endl;
int n = 0;
for(vector<int>::iterator it = v.begin(); it != v.end(); ++it) {
n += *it;
}
cout << time(0) - now << endl;
now = time(0);
for(size_t i = 0; i < v.size(); ++i) {
n += v[i];
}
cout << time(0) - now << endl;
return n != 0;
}