多邊形求面積C++編程

#include <cmath>

using namespace std;

double point[1000000][2],A;

int m;

double det(double x1,double y1,double x2,double y2)

{

return x1*y2-x2*y1;

}

double area()

{

int i;

float temp=0;

for(i=0;i<m-1;i++)

{

temp+=det(point[i][0],point[i][1],point[i+1][0],point[i+1][1]);

}

temp+=det(point[i][0],point[i][1],point[0][0],point[0][1]);

return temp/2;

}

int main()

{

int i;

printf("請輸入多邊形的邊數m:");

while (scanf("%d",&m)!=EOF)

{

if (m==0)break;

printf("請按順序輸入坐標點：\n");

for (i=0;i<m;i++)

{cin>>point[i][0]>>point[i][1]; <br/>}printf("所求 %d 邊形面積為：\n",m);

printf("%.1f\n",area());

}

return 0; }