A=根号下S*（s-a)(s-b)(s-b)其中，A,B和C为三角形的边，2S=a+b+c。给定a,b和c的值

include "stdio.h"
include "math.h"
main()
{
int a,b,c;
float A;
a=b=c=0;
printf("please input the value of a,b,c:");
scanf("%d%d%d",a,b,c);
S=(a+b+c)/2;
A=sqrt(