Chapter - 11: Structures

A linked list is a very common data structure often used to store similar data in memory. While the elements of an array occupy contiguous memory locations, those of a linked list are not constrained to be stored in an adjacent location. The individual elements are stored “somewhere” in memory, rather like a family dispersed, but still bound together. The order of the elements is maintained by explicit links between them. Thus, a linked list is a collection of elements called nodes, each of which stores two item of information—an element of the list, and a link, i.e., a pointer or an address that indicates explicitly the location of the node containing the successor of this list element.


D
Sections
8
Exercises

Write a program to build a linked list by adding new nodes at the beginning, at the end or in the middle of the linked list. Also, write a function disp


#include<stdio.h>
#include<conio.h>
#include<malloc.h>
#include<stdlib.h>
#include<Windows.h>
#define GetSize (struct node*)malloc(sizeof(struct node))

void insert(struct node**, int);
void del(struct node**, int);
void display(struct node*);

struct node
{
	int data;
	struct node* next;
};

int main()
{
	char ans = 'y';
	int num, exit = 1, action;
	struct node *start = NULL;
	printf("\nHello all, this program is of linked list, so go ahead and make your limked list\n\n");
	while (ans == 'y')
	{
		printf("\nEnter the data : ");
		scanf("%d", &num);
		insert(&start, num);
		printf("\nWant to enter another number (y/n) : ");
		while (getchar() != '\n');
		scanf("%c", &ans);
	}
	system("cls");
	while (exit != 0)
	{
		system("cls");
		display(start);
		printf("\n\n\nYou are in menu section\n\n");
		printf("\n0 : Exit\n1 : Insert\n2 : Delete\n3 : Display");
		printf("\n\n\nEnter your choice : ");
		scanf("%d", &action);
		switch (action)
		{
		case 0:
			printf("\nYou are exiting. . . .");
			_getch();
			return 0;
		case 1:
			printf("\nEnter number : ");
			scanf("%d", &num);
			insert(&start, num);
			break;
		case 2:
			printf("\nEnter number to delete : ");
			scanf("%d", &num);
			del(&start, num);
			break;
		case 3:
			display(start);
			break;
		default:
			printf("\nYou have entered a wrong option\,Try againA!!\n");
			exit = 1;
		}
	}
	_getch();
	return 0;
}

void insert(struct node **start, int num)
{
	struct node *help = NULL, *curr = NULL;
	help = GetSize;
	help->data = num;/*This is our new node.*/
	help->next = NULL;
	
	if (*start == NULL)/*Inserting the first element*/
	{
		*start = help;
		return;
	}

	/*Finding the position for the number to insert*/
	for (curr = *start; curr->next != NULL; curr = curr->next);

	curr->next = help;
}

void del(struct node **start, int num)
{
	struct node *curr = *start, *pre = NULL;

	/*Finding the data to be deleted */
	while (curr->data != num)
	{
		pre = curr;
		curr = curr->next;

		/*List ends and the number nor found.*/
		if (curr == NULL)
			break;
	}

	/*Deleting the first node*/
	if (curr == *start)
		*start = curr->next;
	else if (curr == NULL)/*Number not found so just return*/
	{
		printf("\nNumber is not present in the list.");
		return;
	}
	else/*Deleting in between or last node*/
		pre->next = curr->next;

	free(curr);/*Deletion*/
}

void display(struct node *start)
{
	struct node *i = NULL;
	printf("\nYour list\n");
	for (i = start; i != NULL; i = i->next)
		printf("%d\t", i->data);
}

© 2020 Garbage Valuegarbage value logo