圆的面积

题目描述
    Give you the radius of a circle，caculate its area，PI=3.141592653。
输入
The first line of the input is a positive integer N,then follows N lines,each line is a real number represent the radius of the circle.

输出
Output contains N lines,for each line of the input you should output one line, Case K: S,and K(count from 1)represents the number of the circle and S is the area.Keep two digits after the decimal point.

示例输入
3
1
2
3示例输出
Case 1: 3.14
Case 2: 12.57
Case 3: 28.27

#include<stdio.h>
#define PI 3.141592653
int main()
{
	int n,i,r;
	double s;
	scanf("%d",&n);
	for(i=1;i<=n;i++)
	{
		scanf("%d",&r);
		s=PI*r*r;
		printf("Case %d: %.2lf\n",i,s);
	}
	return 0;
}