How to make the following program work?

How to make the following program work? I think there are some place of the following program use the address NULL. But I don't know how to fix the problem. Thank you.

Code:

#include <stdlib.h>

#include <stdio.h>

#include <string.h>

#include <malloc.h>

#include <math.h>

 

typedef struct node /*a node denotes a P_{i,k}^{l}*/

{

 int l,i,k;

} node;

 

 

typedef struct monomial_node /* a monomial denotes a monomial P_{i,k}^{l} \cdots P_{i',k'}^{l'} */

{

 node y;

 int coeff;         /* coeff is s(m_r) */

 struct monomial_node *next; 

 struct monomial_node *head;

 struct monomial_node *tail; 

} monomial_node, *monomial;

 

 

 

typedef struct polynomial_node /* a polynomial denotes a sum of some monomials */

{

 monomial m;

 struct polynomial_node *next; 

 struct polynomial_node *head;

 struct polynomial_node *tail;

} polynomial_node, *polynomial;

 

 

monomial insert(node a, monomial b)          /* insert a factor a to a monomial b such that the first subscripts i's in the new monomial is in increasing order */

{

 monomial p;     

 monomial_node *s;
 
 monomial_node *p1;
 
 
 p=b;
 p1=p->head->next;

 while((p1->y).i >= a.i)          /* find the position */

 {

  p1=p1->next;

  if(p1==p->tail)

  {

    break;

  }

 }

 if(p1==p->tail)
 {
   printf("tail\n");
 }

 s=(monomial)malloc(sizeof(monomial_node));        /* create new node */

 s->y=a;

 s->next=p1->next;     /* insert the node a */

 p1->next=s;

 return p;

}

 

 

monomial create_monomial(int number) /* create a monomial */

{

   monomial m,s;

   monomial p;

   int i;

 
   m=(monomial)malloc(sizeof(monomial_node));
   m->head=m->tail=(monomial)malloc(sizeof(monomial_node));

   if(m->head==NULL)

   {

     return NULL;

   }

 
   m->head->next=m->tail;

   m->tail->next=NULL;

   p=(monomial)malloc(sizeof(monomial_node));

   m->head->next=p;

   p->next=m->tail;   


   printf("Please input the parameters of the heighest weight monomial(for example,  2, 2, 3 denotes the monomial Y^{2}_{2,3}). The first subscripts i of Y's should be in increase order.");

   scanf("%d", &((p->y).l)); 
   scanf("%d", &((p->y).i));
   scanf("%d", &((p->y).k));

  if(number > 1)
  {
   for(i=0;i<number-1;i++)

   {

    s=(monomial)malloc(sizeof(monomial_node));

    scanf("%d", &((s->y).l)); 
    scanf("%d", &((s->y).i));
    scanf("%d", &((s->y).k));
    

    
   
    m=insert(s->y,m);
          

   }
   
  }

 

   return m;

 

}



polynomial create_polynomial(monomial n) /* create a polynomial with only one monomial n */

{

    polynomial m,p;
    
    m=(polynomial)malloc(sizeof(polynomial_node));
    p=(polynomial)malloc(sizeof(polynomial_node));
    m->head=(polynomial)malloc(sizeof(polynomial_node));
    m->tail=(polynomial)malloc(sizeof(polynomial_node));

    m->head->next=p;
    p->m=n;
    p->next=m->tail;
    m->tail->next=NULL;
 
 

    return m;

 

}



 

void print_monomial(monomial m)

{

    monomial p;
    p=(monomial)malloc(sizeof(monomial_node));

    p=m->head->next;

    if(p==m->tail)

    {

             printf("No element. \n");

    }

    while(p!=m->tail)

    {  

       printf("Y^{%d}_{%d,%d}",(p->y).l,(p->y).i,(p->y).k); 

       p=p->next;  

    }

}

 

void print_polynomial(polynomial n)

{

    polynomial p;

    int i=0;

    p=n->head->next;

    if(p==n->tail)

    {

             printf("No element. \n");

    }

    while(p!=n->tail)

    {  

       if(i !=0)

       {

          printf("+");     

       }

       i++;

       print_monomial(p->m);

       p=p->next;  

    }

    printf("\n");

}


int length_monomial(monomial a) 
{
  int len=0;
  monomial_node *b;
  
  b=a->head->next;
  while(b != a->tail)
  {
    len++;
    b=b->next;
  }  
  return len;
}


int length_polynomial(polynomial a) 
{
  int len=0;
  polynomial_node *b;
  
  b=a->head->next;
  while(b != a->tail)
  {
    len++;
    b=b->next;
  }  
  return len;
}



 
int compare_nodes(node a, node b)
{
  int result;
  if(a.l==b.l && a.i==b.i && a.k==b.k)
  {
    result=1;
  }
  else 
  {
    result=0;
  }
  return result;
}



monomial delete_node(node b, monomial a)        
{

 monomial p;    
 monomial_node *p1; 
 
 
 p=a;
 p1=p->head->next;
 p=p->head;

 while(p1 != a->tail)
 {
   if(compare_nodes(p1->y, b)==1)
   {
      p->next = p1->next;
      break;
   }
   p=p->next;
   p1=p1->next;
 }

 return p;

}


int main(int argc, char *argv[])

{

 

 node p;

 

 polynomial FM; 

 polynomial new_monomials; 

 polynomial phi[100][1000];  

 

 monomial s;

 monomial m; 

 monomial mm[1000]; 

 

 int type=1;         

 int ra=2;             

 int l;

 int i,j;

 int number;

 int a;

 int ccc[100][100];

 

 

 

 

  printf("Please input the number of factors.\n");

  scanf("%d", &number);  

  

  m=create_monomial(number);  

 

  FM=create_polynomial(m);  

  

 

  print_monomial(m);

 
  printf("\n");

  print_polynomial(FM);

  printf("\n len(m)=%d", length_monomial(m));
  printf("\n len(FM)=%d", length_polynomial(FM));


  node y,z,w;
  
  y.l=1;y.i=2;y.k=3;

  z.l=1;z.i=2;z.k=3;
  w.l=2;w.i=2;w.k=3;

  printf("\n y=z? %d\n", compare_nodes(y,z));
   printf("\n y=w? %d\n", compare_nodes(y,w));
  


  printf("\n delete y in m:\n");
  
  print_monomial(delete_node(y, m));
 

 

 

 return 0;

}

Why did you open up a new thread when you already have one? And have you bothered to take up Salem's suggestions in this post?

Posts to other thread, please.

Closed