ZOJ-1813 路程与速度

1813:给出车轮直径，转动圈数，花费时间,求路程和平均速度。

简单题。单位换算对即可。
There are 5280 feet in a mile.
There are 12 inches in a foot.

#include<stdio.h>
#include<iostream>
using namespace std;

#define PI 3.1415927
int main()
{
	float diameter;
	int revolution;
	float time;
	double distance;
	double MPH;

	for(int i=1;;i++)
	{
		cin>>diameter;
		cin>>revolution;
		cin>>time;
		if(revolution==0)
			break;
		distance=PI*diameter*revolution/12/5280;
		MPH=distance/(time/3600);
		printf("Trip #%d: %.2f %.2f\n",i,distance,MPH);		
	}
}