请问下面的程序哪里错了，急需各位大神帮忙指出修正。程序题目见附件。急！急！急！！！小女子在此不胜感激

#include <iostream.h>
#include <math.h>
double f(double x)
{
    double t;
    t=cos(x);
    return t;
}
void main()
{
    int n=1,i;
    float m,s,s1,s2=0,s3,h,a=0,b=0.8,c=0.5,p,q,d;
    double eps=1e-8;
    while(fabs(f(n)-f(n-1))>=eps)
    {
        h=(b-a)/(2*n);
        m=(b-a)/(3*n);
        c=0.5;
        d=f(a)-f(b);
        s1=c*d;
        for(i=1;i<=n;i++)
        {
            p=2*f(a+(2*i-1)*h);
            q=f(a+2*i*h);
            s3=p+q;
            s2=s2+s3;
            s1=m*(s1+s2);
        }
        cout<<s<<endl;
    }
}