5-1.c

此源码是著名的教材BeginningLinux Programming中文名字叫Linux程序设计书中的源代码

#include<stdio.h>

#define PI 3.1415926

int main()
{
	int    r = 100;
	double length = 2*PI*r;
	
	printf("The circumference is %f\n",length);
	
	return 0;
}