01: #include <iostream>
02: #include <cmath>
03: using namespace std;
04: 
05: double balance; 
06: /** 
07:    Accumulates interest in the global variable balance
08:    @param p the interest rate in percent
09:    @param n the number of periods the investment is held
10: */
11: void future_value(int p, int n)
12: {  balance = balance * pow(1 + p / 100, n); 
13: }
14: 
15: int main()
16: {  balance = 10000;
17:    future_value(5, 10);
18:    cout << "After ten years, the balance is "
19:         << balance << "\n";
20:    return 0;
21: }