Pentagonal Area(五边形面积)

1、question:

2、code:

#include<iostream>
#include<cstdio>
#include<cmath>
using namespace std;
double area(double x,double y,double z)
{
double s,p,m;
p=(x+y+z)/2;
m=p*(p-x)*(p-y)*(p-z);
s=sqrt(m);
return s;
}
double a[12],s;
int main()
{
for(int i=1;i<=7;i++)
scanf("%lf",&a[i]);
s=area(a[1],a[5],a[6])+area(a[2],a[6],a[7])+area(a[3],a[4],a[7]);
printf("%0.2lf",s);
return 0;
}

3、operationnal result: