what does auto do in c++ code example

Example 1: auto in c++

int foo = 0;
auto bar = foo;  // the same as: int bar = foo; 
// type of bar is the type of the value used to initialize it

Example 2: auto in cpp

#include<iostream>
#incllude<vector>
using namespace std;

int main() {
   vector<int> vec(10);       // Auto deduce type to be iterator of a vector of ints.
   for(auto it = vec.begin(); it != vec.end(); vec ++)
   {
      cin >> *it;
   }
   return 0;
}