Check out example codes for "find index of element in vector c++". It will help you in understanding the concepts better.

Code Example 1

``````// C++ program to find the index
// of an element in a vector

#include <bits/stdc++.h>
using namespace std;

// Function to print the
// index of an element
void getIndex(vector<int> v, int K)
{
auto it = find(v.begin(), v.end(), K); // returns iterator to element K

// If element was found
if (it != v.end()) {
// calculating the index
// of K
int index = distance(v.begin(), it);
cout << index << endl;
}
else {
// If the element is not
// present in the vector
cout << "-1" << endl;
}
}
// Driver Code
int main()
{
// Vector
vector<int> v = { 1, 45, 54, 71, 76, 17 };
// Value whose index
// needs to be found
int K = 54;
getIndex(v, K);
return 0;
}``````

Code Example 2

``````// CPP program to illustrate
// std::find
// CPP program to illustrate
// std::find
#include<bits/stdc++.h>

int main ()
{
std::vector<int> vec { 10, 20, 30, 40 };

// Iterator used to store the position
// of searched element
std::vector<int>::iterator it;

// Print Original Vector
std::cout << "Original vector :";
for (int i=0; i<vec.size(); i++)
std::cout << " " << vec[i];

std::cout << "\n";

// Element to be searched
int ser = 30;

// std::find function call
it = std::find (vec.begin(), vec.end(), ser);
if (it != vec.end())
{
std::cout << "Element " << ser <<" found at position : " ;
std::cout << it - vec.begin() << " (counting from zero) \n" ;
}
else