how to delete nodes

[winber]

hi guys i need some help can you guys help me at deleting nodes I'm not yet that good in linked list and I can only delete the first node but I can't delete nodes in the middle and at the last help please I'm making a student database where we can create courses and student accounts thanks

void deleteclass(ptrClass *pFirst,int arr[])
{
     int a;
     int i=0;
     ptrClass current,trail;
     
     current = *pFirst;
     
     //dview();
    
    
    
     if(arr[0] != 0)
     {
     do
     {
     //dview();          
     printf("\t\t\t[1] for next\n\t\t[2] for Previous \n\t\t[3] for delete\n\t\t[4] Exit\n\n");          
     printf("\t\t[course code] : %s \n\n",current->coursecode);
        printf("\t\t[section] : %d \n\n",current->section);
            printf("\t\t[number of the units] : %d \n\n",current->units);
               printf("\t\t[The schedule] : %s \n\n",current->schedule);
               printf("\t\t[Starting time %d:%d End Time %d:%d \n\n",current->pTime.shours,current->pTime.smin,current->pTime.ehours,current->pTime.emin);
                  printf("\t\t[Name of the lecturer] : %s \n\n",current->lecturer);
                     printf("\t\t[total slots] : %d\n\n",current->slots);
     
     scanf("%d",&a);  
     //for menu functions
     if(a==1)
     {
     system("cls");    
     if(current->pNext != NULL)   
     current= current->pNext;
     
     if(current->pNext == NULL)
     {
       system("cls");
}
    
     i++;
     if(i > arr[0])
     current = current->pPrev;
     }
     else if(a==2)
     {
     system("cls");   
     current = current->pPrev; 
     i--;          
       if( i < 0)
       i = arr[0] - 1;  
     }
     
     if(a == 3)
     {
        
      
      if(*pFirst == current)
      *pFirst = (*pFirst)->pNext;  
      
    //  else if(current->pNext != NULL)
      
      else if(current->pNext == NULL)
    {
      current->pPrev = current->pNext;
      
      }
    
      free(current);
        
      }
     
     else if(a==4)
     {
     system("cls");    
     i=7; 
     }               
     }while(i<6);
     system("cls");
}
      else
     printf("\n\n\n\n\n\n\t\t\t\t[There's no class created] \n");
     
     sleep(1000);
     system("cls");
     }

[claudiu]

First of all your indentation is crap, which makes this very very difficult to read. Moreover, you are using obscure variable names like a, and arr which could pretty much be anything.

Also, if i were to take a guess your problems stem from the fact that you are typedefining pointers to other type names which makes the program extremely unreadable. Don't use typedefs unless you really have to, especially if you are a beginner. Just write the whole struct whatever* instead of typedefing it to ptrWhatever.

What is the effect compilation wise or run-time wise of this code?