//3_1.cpp
#include <iostream>
using namespace std;

double power (double x, int n);

void main(void)
{
	cout <<  "5 to the power 2 is " << power(5,2) << endl; 
	//函數(shù)調用作為一個表達式出現(xiàn)在輸出語句中。
}

double power (double x, int n)
{
	double val = 1.0;
	while (n--)
	val *= x;
	return(val);
}