#include "stdio.h"
#include "conio.h"
#include "math.h"
main()
{
float a,b,c;
float s,area;
scanf("%f,%f,%f",&a,&b,&c);
if(a+b>c&&a+c>b&&b+c>a)
{
s=(a+b+c)/2;
area=sqrt(s*(s-a)*(s-b)*(s-c));
printf("%f",area);
if(a==b==c)
{
printf("deng bian sang jue xing");
if (a==b||a==c||b==c)
printf("deng yao sang jue xing ");
else if((a*b+b*b=c*c)||(a*a+c*c==b*b)||(b*b+c*c==a*a))
printf("zhi jue sang jue xing");
else printf("yi bang sang jue xing");
}
else printf("bu neng zu ceng sang jue xing");
getch();
}
}

else if (==)

if (a=b=c),不能这样写，应该if(a==b&&b==c)

感觉你逻辑有点混乱