#include <math.h>
int main(void)
{
float a, b, c, dian1[2], dian2[2], dian3[2], l, s;
cout<<"依次輸入三個點的坐標"<<endl;
cin>>dian1[0];
cin>>dian1[1];
cin>>dian2[0];
cin>>dian2[1];
cin>>dian3[0];
cin>>dian3[1];
a = (float)sqrt((dian1[0] - dian2[0]) * (dian1[0] - dian2[0]) + (dian1[1] - dian2[1]) * (dian1[1] - dian2[1]));
b = (float)sqrt((dian1[0] - dian3[0]) * (dian1[0] - dian3[0]) + (dian1[1] - dian3[1]) * (dian1[1] - dian3[1]));
c = (float)sqrt((dian2[0] - dian3[0]) * (dian2[0] - dian3[0]) + (dian2[1] - dian3[1]) * (dian2[1] - dian3[1]));
l = a + b + c;
s = (float)sqrt(l / 2 * (l / 2 - a) * (l / 2 - b) * (l / 2 - c));
cout<<a<<endl;
cout<<b<<endl;
cout<<c<<endl;
cout<<l<<endl;
cout<<s<<endl;
return 1;
}