CPP

cpp auto

//When using auto variables, the data type is decided in initialisation

#include <iostream>
using namespace std;

int main() {
    auto IntegerVar=25;   //creates integer type variable
    auto FloatVar=26.77;  //creates float type variable
    auto StringVar="Hello";  //creates string type variable
    auto CharVar="C";   //creates char type variable
  
    cout<<"CREATING VARIABLES USING AUTO DATA TYPE

";
    cout<<"Integer: "<<IntegerVar<<endl;
    cout<<"Float: "<<FloatVar<<endl;
    cout<<"String: "<<StringVar<<endl;
    cout<<"Char: "<<CharVar;
    
    cout<<"

";
    return 0;
}

auto& in c++

    Use auto && for the ability to modify and discard values of the sequence within the loop. (That is, unless the container provides a read-only view, such as std::initializer_list, in which case it will be effectively an auto const &.)
    Use auto & to modify the values of the sequence in a meaningful way.
    Use auto const & for read-only access.
    Use auto to work with (modifiable) copies.

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

for auto c++

for (auto&& [first,second] : mymap) {
    // use first and second
}

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;
}

auto i cpp

auto n=1;
// this will make the type int, and you can't change trough the program;
cout << n;
// OR
auto n="how you doin'";
cout << n;