chiper out area.txt

求面积

#include<stdio.h>
#include<math.h>
#define S(a,b,c)(a+b+c)/2
#define AREA(a,b,c) sqrt(S(a,b,c)*S(a,b,c)-a)*(S(a,b,c)-b)*(S(a,b,c)-c))
void main()
{float a,b,c;
 print("input a,b,c:");
 scanf("%f,%f,%f",&a,&b,&c);
 if(a+b>c&&a+c>b&&b+c>a)
    printf("area:%8.2f\n",AREA(a,b,c));
    else
    printf("is not a triangle!");
 }