通过半径计算圆直径、周长和面积

/* caculate the circle *//* Input: radius *//* Output:caculate the diameter perimeter and area */#include<stdio.h>int main(){    /* declaration */    int int_radius;    /* declaration */    float float_Pi = 3.14159;    /* prompt */    printf("Please Enter the radius: ");    /* prompt */    scanf("%d", &int_radius);    /* caculate the diameter */    printf("The diameter is: %d\n", int_radius * 2);    /* caculate the perimeter */    printf("The perimeter is: %f\n", int_radius * 2 * float_Pi);    /* caculate the area */    printf("The area is: %f\n", int_radius * int_radius * float_Pi);        return 0;}