为甚麽我这个代码不对啊 求解答~~

#include<bits/stdc++.h>
using namespace std;
int main()
{
    double a;
    double b;
    double c;
    double p;
    double s;
    scanf("%lf %lf %lf %lf",&a,&b,&c,&p);
    p=1\2*(a+b+c);
    s=srqt(p*(p-a)*(p-b)*(p-c));
    s=printf("%0.1lf\n",ans);
    return 0;
}

喵