若输入3、4、5，程序的输出结果为 【6】 。
#include "math.h"
main ( )
float a, b, c, s, area;
scanf("%f,%f,%f",&a,&b,&c);
s=1.0/2*(a+b+c);
area=sqrt (s* (s-

• a) * (s-
• b) * (s-
• c));
  printf ("a=%7.2f,b=%7.2f, c=%7.2f, s=%7.2f", a,b, c, s);
  printf ("area=%7.2f\n", area);