Thread: lists help

Hi, i'm new and i've useing C programming language for a couple of months and i have problem: i can't sort lists
e.g. : i type :3 and then 1 and 2 and i have to print 1/n 2/n 3/n.
How to do this? Please help!!!
i 've tried to do somethong bit i couldn't ;(

Code:

#include<stdio.h>
#include<string.h>
#include<stdlib.h>
int n;
typedef struct Element  *PElement;

struct Element {
       int data;
       PElement next; 
};
PElement stack,tmp2,tmp3;

int var1=0,var2=0; 
PElement push ()
{
         
         PElement tmp = (PElement) malloc(sizeof(struct Element));
         
         
         
         printf("type some digit "); 
         scanf("%d", &tmp->data);
         tmp2 = tmp;
         var1 =tmp2->data;

         printf("var1 :%d var2 :%d \n",var1, var2);
         if(var1 < var2)
         {  

             tmp->next = stack;

         }
         
         else 
         {

             tmp -> next = stack;
             stack = tmp;
             tmp3 = stack;
             var2 = tmp3->data;
         }

         printf("var1 :%d var2 :%d \n",var1, var2);
         return stack;

}


PElement pop ()
{
         
         while(stack != NULL)
         {
             printf("Data is %d\n" , stack->data);
             stack = stack -> next; 
             printf("\n\n\n");

         continue;
         }
         

        
        
        return stack; 
}


int main () 
{
    for(;;)
    {
        printf("1 push \n");
        printf("2 pop\n");
        scanf("%d",&n);
        switch (n)
        {
               case 1:push();
               break;
               case 2:pop();
               break;
               default:printf("MISTAKE");
         }
    }    
    
    getchar(); 
      
    return 0;  
}

i know this is wrong but i don't know how to fix it, i'm new in programming and i haven't
met such problems before and i need the code for tomorrow so if you can help me untill then i'll be very thankful and appreciatеd thank you for helping me

Originally Posted by hk_mp5kpdw

What's with the global variables. n, var1, var2, tmp, tmp2 should not be globals. stack should be in main and passed into/out of functions as appropriate.

so what am i supposed to do? i don't know. if you know colud you tell? please?

Originally Posted by MK27

var1 and var2 should be local to push().

"stack" is maybe what most people would call "head", except your pop() function is wrong -- it will just go thru the whole list (not pop one item at a time off), and you will lose a pointer to your first element (which was in "stack", ie, the head), so you will now have no way to access the list.

The normative way would be to declare the head in main and then use an initialize function. You should find a link list tutorial and use that. You must have these basics in order before you have a hope of sorting.

thank you! now i'm tottaly confused, but not because of you, but because of my lack of knowledge . Thank you, really
i appriciate this