#include <iostream.h>
#include <conio.h>

void main()
{
clrscr();
long int svalue;
float commission;
cout << "Enter the total sale value : " << endl;
cin>>svalue;
if(svalue<=10000)
{
commission=svalue*5/100;
cout << "For a total sale value of $" << svalue << ", ";
cout << "the agent's commission is $" << commission;
}
else if(svalue<=25000)
{
commission=svalue*10/100;
cout << "For a total sale value of $" << svalue << ", ";
cout << "the agent's commission is $" << commission;
}
else if(svalue>25000)
{
commission=svalue*20/100;
cout << "For a total sale value of $" << svalue << ", ";
cout << "the agent's commission is $" << commission;
}
getch();
}

This program takes in the total sale value as a screen input from the user.
The program then calculates the agent's commission with the help of the 'IF-ELSE' command as follows :
5% if the total sale value is less than or equal to $10000.
10% if the total sale value is less than or equal to $25000.
20% if the total sale value is greater than $25000. It then outputs the agent's commission using the 'cout' command.