This is a code of C++ programming to find mean of 3 numbers.

#include <iostream>
using namespace std;
int main ()
{ float a,b,c,mean;

	//input
	cout<<"Enter the first number >>"; cin>> a;
	cout<<"Enter the second number >>"; cin>> b;
	cout<<"Enter the third number >>"; cin>> c;
	//process
	mean=(a+b+c)/3;
	//output
	cout<<"Result is :"<<mean;
	return 0;
}