list.c

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

struct node {
  int data;
  struct node *next;
} *head = NULL;

void insert_beg(int val);
void create_node(int val);
void insert_end(int val);
void insert_after(struct node *q, int val);
void traversal();
void deletion(struct node *p);
struct node *find(int val);

int main() {
  struct node *p, *q;
  int choice, val, ele;
  do {
    printf("\n--------------------------------");
    printf("\nOpertation on singly linked list");
    printf("\n--------------------------------");
    printf("\n0. Creation of a node");
    printf("\n1. Insert node at first");
    printf("\n2. Insert node at last");
    printf("\n3. Insert node at position");
    printf("\n4. Delete node from any position");
    printf("\n5. Search element in the linked list");
    printf("\n6. Display list");
    printf("\n7. Exit");
    printf("\nEnter your choice: ");
    scanf("%d", &choice);

    switch (choice) {
    case 0:
      printf("\nEnter the value to be inserted: ");
      scanf("%d", &val);
      create_node(val);
      traversal();
      break;
    case 1:
      printf("\nEnter the value to be inserted: ");
      scanf("%d", &val);
      insert_beg(val);
      traversal();
      break;
    case 2:
      printf("\nEnter the value to be inserted: ");
      scanf("%d", &val);
      insert_end(val);
      traversal();
      break;
    case 3:
      printf("\nEnter the value to be inserted: ");
      scanf("%d", &val);
      printf("\nEnter the element after which value to be inserted: ");
      scanf("%d", &ele);
      q = find(ele);
      if (q != NULL) {
        insert_after(q, val);
        traversal();
      } else {
        printf("\nNot found");
      }

      break;
    case 4:
      printf("\nEnter the element to be deleted: ");
      scanf("%d", &val);
      p = find(val);
      if (p != NULL) {
        deletion(p);
        printf("\nElements after deletion");
        traversal();
      } else {
        printf("\nElement not found");
      }
      break;
    case 5:
      printf("\nEnter the value to be searched: ");
      scanf("%d", &val);
      p = find(val);
      if (p != NULL)
        printf("\nElement found");
      else
        printf("\nElement not found");
      break;
    case 6:
      traversal();
      break;
    case 7:
      printf("\nExiting");
      break;
    default:
      printf("\nInvalid input");
      break;
    }

  } while (choice < 7);

  return 0;
}

void create_node(int val) {
  struct node *p;
  p = malloc(sizeof(struct node));
  p->data = val;
  p->next = NULL;
  head = p;
}

void insert_beg(int val) {
  struct node *p;
  p = malloc(sizeof(struct node));
  p->data = val;
  p->next = head;
  head = p;
}
void insert_end(int val) {
  struct node *p, *q;
  p = malloc(sizeof(struct node));
  p->data = val;
  p->next = NULL;
  q = head;
  while (q->next != NULL)
    q = q->next;
  q->next = p;
}

void insert_after(struct node *q, int val) {
  struct node *p;
  p = malloc(sizeof(struct node));
  p->data = val;
  p->next = q->next;
  q->next = p;
}

void deletion(struct node *p) {
  struct node *q;
  if (p == head) {
    head = p->next;
    free(p);
  } else {
    q = head;
    while (q->next->data != p->data)
      q = q->next;
    q->next = p->next;
    free(p);
  }
}

struct node *find(int val) {
  struct node *q;
  q = head;

  while (q->data != val)
    q = q->next;
  return q;
}

void traversal() {

  struct node *q;
  q = head;
  printf("\n-----List Start------\n");
  while (q != NULL) {
    if (q->next == NULL)
      printf("%d", q->data);
    else
      printf("%d-->", q->data);
    q = q->next;
  }
  printf("\n-----List End------\n");
}