    01: #include <iostream>
    02: #include <cmath>
    03:
    04: using namespace std;
    05:
    06: double balance;
    07:
    08: /**
    09:    Accumulates interest in the global variable balance
    10:    @param p the interest rate in percent
    11:    @param n the number of periods the investment is held
    12: */
    13: void future_value(int p, int n)
    14: {
    15:    balance = balance * pow(1 + p / 100, n);
    16: }
    17:
    18: int main()
    19: {
    20:    balance = 10000;
    21:    future_value(5, 10);
    22:    cout << "After ten years, the balance is "
    23:       << balance << "\n";
    24:    return 0;
    25: }