004_sll_delete_last.cpp

#include <stdio.h>
#include <stdlib.h>

struct node {
    int num;                    
    struct node *nextptr;       
}*stnode;                       

void createNodeList(int n);    
void LastNodeDeletion();        
void displayList();             

int main(){
    int n,num,pos;
    printf("\n\n Linked List : Delete the last node of Singly Linked List :\n");
    printf("---------------------------------------------------------------\n");

    printf(" Input the number of nodes : ");
    scanf("%d", &n);
    createNodeList(n);

    printf("\n Data entered in the list are : \n");      
    displayList();
    LastNodeDeletion();
    printf("\n The new list after deletion the last node are  : \n"); 
    displayList();
    return 0;
}

void createNodeList(int n){
    struct node *fnNode, *tmp;
    int num, i;

    stnode = (struct node *)malloc(sizeof(struct node));
    if(stnode == NULL){
        printf(" Memory can not be allocated.");
    }
    else{
        printf(" Input data for node 1 : ");
        scanf("%d", &num);

        stnode-> num = num;         
        stnode-> nextptr = NULL;   
        tmp = stnode;

        for(i = 2; i <= n; i++){
            fnNode = (struct node *)malloc(sizeof(struct node));

            if(fnNode == NULL){
                printf(" Memory can not be allocated.");
                break;
            }
            else{
                printf(" Input data for node %d : ", i);
                scanf(" %d", &num);

                fnNode->num = num;      // Assign data to the current node
                fnNode->nextptr = NULL; // Links the address field to NULL

                tmp->nextptr = fnNode;  // Links previous node i.e. tmp to the fnNode
                tmp = tmp->nextptr;
            }
        }
    }
} 

void LastNodeDeletion()
{
    struct node *toDelLast, *preNode;
    if(stnode == NULL){
        printf(" There is no element in the list.");
    }
    else
    {
        toDelLast = stnode;
        preNode = stnode;

        while(toDelLast->nextptr != NULL){
            preNode = toDelLast;
            toDelLast = toDelLast->nextptr;
        }
        if(toDelLast == stnode)  {
            stnode = NULL;
        }
        else{
          
            preNode->nextptr = NULL;
        }

        free(toDelLast);
    }
}
void displayList()
{
    struct node *tmp;
    if(stnode == NULL)
    {
        printf(" No data found in the empty list.");
    }
    else
    {
        tmp = stnode;
        while(tmp != NULL)
        {
            printf(" Data = %d\n", tmp->num);   
            tmp = tmp->nextptr;                
        }
    }
}