7.1
#include<iostream> void simple(); int main() { using namespace std; cout << "main() will call the simple() function:\n"; simple(); cout << "main() is finished with the simple() function.\n"; system("pause"); return 0; } void simple() { using namespace std; cout << "I'm but a simple function.\n"; }7.2
#include<iostream> void cheers(int); double cube(double x); int main() { using namespace std; cheers(5); cout << "Give me a number: "; double side; cin >> side; double volume = cube(side); cout << "A" << side << "-foot cube has a volume of "; cout << volume << " cubic feet.\n"; cheers(cube(2)); system("pause"); return 0; } void cheers(int n) { using namespace std; for (int i = 0; i < n; i++) cout << "cheers! "; cout << endl; } double cube(double x) { return x*x*x; }