read element from std::vector code example
Example: vector by index c++
// vector::operator[]
#include <iostream>
#include <vector>
int main ()
{
std::vector<int> myvector (10); // 10 zero-initialized elements
std::vector<int>::size_type sz = myvector.size();
// assign some values:
for (unsigned i=0; i<sz; i++) myvector[i]=i;
// reverse vector using operator[]:
for (unsigned i=0; i<sz/2; i++)
{
int temp;
temp = myvector[sz-1-i];
myvector[sz-1-i]=myvector[i];
myvector[i]=temp;
}
std::cout << "myvector contains:";
for (unsigned i=0; i<sz; i++)
std::cout << ' ' << myvector[i];
std::cout << '\n';
return 0;
}