📅  最后修改于: 2022-03-11 15:04:35.649000             🧑  作者: Mango
#include
#define PI 3.142
int main(){
float R, A;
printf("Enter the radius: \n");
scanf("%f", &R);
A = PI * R * R;
printf("Area is: %f\n", A);
}