请帮忙调试一个c语言的程序！急急！！

#include <stdio.h>
#include<stdlib.h>
#include<math.h>
int main ()
{
//Inputs
double f(double x, double y, double z);
double d2f(double x, double y, double z);
double d3f(double x, double y, double z);
double a, b, tol;
int iter, maxIter, n, i;
float ya, yb, dy;//重定义a，b
printf("Enter the initial (a) and final (b) values of x:");
scanf("%f%f",&a,&b);
printf("Enter boundary values of y at x=a (ya) and x=b (yb):");
scanf("%f%f", &ya,&yb);
printf("Enter number of subdivision n:");
scanf("%d", &n);//定义是整形。存的时候又用f??
float A[3][n+1], y[n+1]; // tridiagonal. We do not use A(.,0)
double h = (b-a)/(n+1);
double alpha = y[0];
double beta = y[n+1];
const int SUBD = 0;
const int DIAG = 1;
const int SUPD = 2;
float B[n+1];
B[0] = 0;
// Initial guess at solution
for(i=1; i<