what is c 2b 2b function

1// function example
2#include <iostream>
3using namespace std;
4
5int addition (int a, int b)
6{
7  int r;
8  r=a+b;
9  return r;
10}

1#include <iostream>
2
3using namespace std;
4
5void function(){
6    cout << "I am a function!" << endl;
7}
8
9int main()
10{
11    function();
12
13    return 0;
14}

1return_type function_name( parameter list ) {
2   body of the function
3}
4