c++ vector index of element code example

Example 1: get index of value c++

vector<int> arr = { 6, 3, 5, 2, 8 };
vector<int>::iterator itr = std::find(arr.begin(), arr.end(), elem);

if (itr != end(arr)) {
	cout << "Element " << elem << " is present at index " << distance(arr, itr) << " in the given array";
}
else {
	cout << "Element is not present in the given array";
}

Example 2: c++ get vector element by index

vectorName[5];
// Simple

Example 3: 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;
}