#define PI 3.14
void main()
{
float r,l,area
printf("please input r:\n")
scanf("%f", &r)
if(r>=0)
{
area=PI*r*2
l=2*PI*r
printf("the area is %.2f\n", area)
printf("the l is %.2f\n", l)
}
else
printf("Input error!\n")
return 0
}
pow函数原型是:double pow(double x, double y);
参数和返回值都是double,不是int。
#include <stdio.h>
#include<math.h>
int main()
{
double x=1.07,y=10.0
printf("%lf",pow(x,y))
return 0
}
#include <stdio.h>#define PI 3.1415927
int main()
{
double r
scanf("%lf",&r)
printf("%lf,%lf,%lf\n", 2*PI*r, PI*r*r, PI*r*r*r*4/3)
return 0
}