#define s(a,b,c) (a+b+c)/2
#define area(s,a,b,c) sqrt(s*(s-a)*(s-b)*(s-c))
main()
{int a,b,c,s,area;
a=5;b=4,c=3;
s=s(a,b,c);
area=area(s,a,b,c);
printf("%d",area);
getch();
}

#define s(a,b,c) (a+b+c)/2
#define area(s,a,b,c) sqrt(s*(s-a)*(s-b)*(s-c))
#include<math.h>
main()
{int a,b,c,s,area;
a=5,b=4,c=3;
s=s(a,b,c);
area=area(s,a,b,c);
printf("%d",area);
getch();
}

就是缺两个头文件，另外area定义为float好些

#define s(a,b,c) (a+b+c)/2
#define area(s,a,b,c) sqrt(s*(s-a)*(s-b)*(s-c))
#include<math.h>
main()
{int a,b,c,s,;
float area;
a=5,b=4,c=3;
s=s(a,b,c);
area=area(s,a,b,c);
printf("%d",area);
getch();
}