迭代法求解AX=B方程组

请问这个程序为什么能运行，啥结果也没有
double Jacobi(double **a, double **g, double *x1,double *x0)//雅克比迭代法
{
    double sum,err=0.0;
    x0=(double *)malloc(sizeof(double )*n7);
    x1=(double *)malloc(sizeof(double )*n7);

    for(i=0;i<=(n+1)*(n+1);++i)
    {
        x0[i]=0.0;
        x1[i]=0.0;
    }
    for (k=0;k<maxn;k++)//k为迭代次数
    {
         max_error=0.0;
        for (i=0;i<=(n+1)*(n+1)-1;i++)
        {
            sum=0.0;
            for (j=0;j<=(n+1)*(n+1)-1;j++)
            {
                if(j!=i)
                    sum+=a[i][j]*x0[j];
            }
            x1[i]=(b[i]-sum)/a[i][i];
        }
        for(i=0;i<=(n+1)*(n+1)-1;i++)
        {
            err=fabs(x1[i]-x0[i]);//绝对误差
            if(err>max_error)
                max_error=err;
                x0[i]=x1[i];
        }
        if (err<pow(10,-7))
            break;
   }
     printf("经过%d次雅克比迭代得到以下解向量\n", k+1);

}