error in the sorting code it removes some output from the linked list

[ehab mohamed]

error in the sorting code it removes inputs in the linked list when the p->data > q->data

#include<stdio.h>
 
struct node{
int data;
node* next;
};
 
node* insert (node*list, int x)
{node *m=new(node);
node*q=list;
node*p=new(node);
p->data=x;
 
if(q==NULL)
{p->next=list;
list=p;
return list;}
 
else if(p->data > q->data)
{ while(q!=NULL){
m=q->next;
q->next=p;
p->next=m;
q=q->next;
}
}
 
else
{
 
p->next=q;
list=p;
q=q->next;
 
return list;
}
return list;}
 
 
void display (node*list)
{node*p=list;
while (p!=NULL)
{printf("%d ",p->data);
p=p->next;
}}
 
int main()
{node*list=NULL;
 
list=insert(list,5);
list=insert(list,4);
list=insert(list,3);
list=insert(list,9);
 
 
 
printf("The sorted linked list=\n");
display(list);
 
return 0;
 
}

[donbock]

Please describe in more detail what goes wrong.

By the way, the definition of m has an initializer that creates a new node. You unconditionally discard this new node. I don't know if this is a memory leak, but it is certainly unnecessary.

[ehab mohamed]

when i run the program the output is 3 9
it removes the first two numbers 4 & 5

[ehab mohamed]

there is some thing goes wrong in this condition

else if(p->data > q->data)
{ while(q!=NULL){
m=q->next;
q->next=p;
p->next=m;
q=q->next;
}
}

[donbock]

The elsif block inserts node p in the list over and over again.

[ehab mohamed]

what can i do ?? to solve it.......
can u explain ??

[donbock]

Suppose a list were a node (with data field ignored) rather than a node pointer. Doing so would make the insert function a little bit simpler and the display function a little bit more complicated.

Suppose you had a function that creates a new node and connects it into the list immediately after the node specified as an argument.

node *insertAfter(node *priorNode, int x);

Then all your insert function has to do is traverse the list looking for where the new node should go and then call insertAfter.

By the way, your program should fail gracefully if it can't allocate the new mode because no memory is available. That's the reason I suggested insertAfter return a value (the address of the new node) so that the caller can recognize an out-of-memory failure.