getch()

#include<iostream>
#include<conio.h>
using namespace std;

int main()
{
cout<<"Hi"<<endl;
getch();         //Screen is paused till the user presses a button.
cout<<"By"<<endl;
}

=========================================================================================

#include<iostream>
#include<conio.h>
using namespace std;

int main()
{
cout<<"Hi"<<endl;
int a = getch();         //Screen is paused till the user presses a button and that pressed button's ASCII will be stored in a.
cout<<a;
}

Did you see how useful is it?
Once you have stored the ASCII value, you can compare it. Let me clarify what I mean.


#include<iostream>
#include<conio.h>
using namespace std;

int main()
{
cout<<"Hi"<<endl;
int a = getch();         //Screen is paused till the user presses a button and that pressed button's ASCII will be stored in a.
if (a == 97)
cout<<"How dare you to press \"a\""<<endl;
else
if (a == 98)
cout<<"How dare you to press \"b\""<<endl;
else
cout<<"You pressed a key other than A and B."<<endl;
}