题解 | 三角形面积

#include <bits/stdc++.h>
using namespace std;

struct point{
    double x,y;
    point(double A,double B){
        x=A,y=B;
    }
    point() = default;
};

struct triangle{
    point a,b,c;
    triangle(point A,point B,point C){
        a=A,b=B,c=C;
    }
    triangle() = default;
};

double getArea(triangle T){ 
    double x1=T.a.x,y1=T.a.y;
        double x2=T.b.x,y2=T.b.y;
        double x3=T.c.x,y3=T.c.y;
        double 面积=abs((x2-x1)*(y3-y1)-(x3-x1)*(y2-y1))/2;
        return 面积;
    // TODO: 计算三角形T的面积
}

































































































































































































int main(){
    int x, y;
    cin >> x >> y;
    point a(x, y);
    cin >> x >> y;
    point b(x, y);
    cin >> x >> y;
    point c(x, y);
    triangle T(a, b, c);
    cout << fixed << setprecision(2) << getArea(T) << endl;
    return 0;
}