求三角形面积，不知道sqrt输入

Question

Answer 1

#include <stdio.h>
#include <math.h>
int main ()
{
  float a=3, b=5, c=7, s;
  s=(a + b + c)/2.0;
  printf("%f\n", sqrt(s*(s-a)*(s-b)*(s-c)));
  return 0;
}