What is being suggested is not really a hard substitution here:
(Technically you need #include <cstdlib> at the top as well, I guess.)Code:#include <iostream> using namespace std; int main() { int gallons, liters; cout << "Enter number of gallons: "; cin >> gallons; liters = gallons * 4; cout << "Liters: " << liters; system("PAUSE"); return 0; }