海伦公式计算三角形面积

解题思路:

注意事项:计算值要设置为double

参考代码:

#include<stdio.h>

#include<math.h>

double distance(float x1, float y1, float x2, float y2);//计算两点间距 

int main(void)

{

    float x1,x2,x3,y1,y2,y3;

    double a,b,c,p,s;

    scanf("%f %f",&x1,&y1);

    scanf("%f %f",&x2,&y2);

    scanf("%f %f",&x3,&y3);

    a  = distance(x1, y1, x2, y2);

    b = distance(x1, y1, x3, y3);

    c = distance(x2, y2, x3, y3);

    p = (a+b+c)/2;

    s = sqrt(p*(p-a)*(p-b)*(p-c));//海伦公式 

    printf("%.2f\n",s);

    return 0;

 } 

double distance(float x1, float y1, float x2, float y2)

 {

      double dis = sqrt(pow((x1-x2),2) + pow((y1-y2),2));

      return dis;

 }