#include <stdio.h>
#include <math.h>
void main ( )
{ double a,b,c,s,area;
printf("please enter a,b,c:");
scanf("%lf,%lf,%lf",&a,&b,&c);
if (a+b>c && b+c>a && c+a>b)
{ s=0.5*(a+b+c);
area=sqrt(s*(s-a)*(s-b)*(s-c));
printf("area=%6.2f\n",area);
}
else printf("It is not a trilateral.\n");
}
please enter a,b,c:2,3,6↙
It is not a trilateral.
