Answer:
The program in C++ is as follows:
#include <iostream>
using namespace std;
int main(){
  int qty;
  float discount = 0;
  cout<<"Quantity: ";
  cin>>qty;
  int cost = qty * 100;
[tex]i f (cost > 1000)[/tex] { Â Â Â Â [tex]discount=cost * 0.10[/tex]; Â Â Â Â }
  cout<<"Cost: "<<cost - discount;
  return 0;
}
Explanation:
This declares the quantity as integer
  int qty;
This declares and initializes discount to 0
  float discount = 0;
This prompts the user for quantity
  cout<<"Quantity: ";
This gets input for quantity
  cin>>qty;
This calculates the cost
  int cost = qty * 100;
If cost is above 1000, a discount of 10% is calculated
[tex]i f (cost > 1000)[/tex] { Â Â Â Â [tex]discount=cost * 0.10[/tex]; Â Â Â Â }
This prints the cost
  cout<<"Cost: "<<cost - discount;