#include
#include
float fun(float x1,float x2,float y1,float y2);
main()
{
float a,b,c,p,S;
int x1,x2,y1,y2;
printf("请输入 B、C 两点坐标："); scanf(" d, d, d, d",&x1,&y1,&x2,&y2);
a=fun(x1,x2,y1,y2);
printf("请输入 A、C 两点坐标："); scanf(" d, d, d, d",&x1,&y1,&x2,&y2); b=fun(x1,x2,y1,y2);
printf("请输入 A、B 两点坐标："); scanf(" d, d, d, d",&x1,&y1,&x2,&y2); c=fun(x1,x2,y1,y2);
p=(a+b+c)/2;
S=sqrt(p*(p-a)*(p-b)*(p-c)); printf("三角形的面积为：f",S);
}
float fun(float x1,float x2,float y1,float y2)
{
return sqrt((x1-x2)*(x1-x2)+(y1-y2)*(y1-y2));
}
