What is type deduction in C++?

Type inference or deduction refers to the automatic detection of the data type of an expression in a programming language. It is a feature present in some strongly statically typed languages. In C++, the auto keyword(added in C++ 11) is used for automatic type deduction. For example, you want to create an iterator to iterate over a vector, you can simply use auto for that purpose. 

Example

#include<iostream>
#include<vector>
using namespace std;
int main() {
   vector<int> arr(10);
   
   for(auto it = arr.begin(); it != arr.end(); it ++) {
      cin >> *it;
   }
   return 0;
}

In the above program, it will automatically get the type std::vector<int>::iterator.