use by click on keyboard !!

Question

in console application ( c++ , c#, java , python )...
how i get keyboard do some functions in my program.. such as when i click on E button my program print "hello world!" or other ..

Answer 1

Maybe switching switch acording to the user input

Answer 2

c++

#include <iostream.h>
void main()
{
char a;
cin>>a;
if(a=='e')
{
cout<<"Hello World";
}