added singly linked list

singly_linked_list.cpp

@@ -0,0 +1,188 @@
+#include<stdio.h>
+#include<conio.h>
+#include<stdlib.h>
+
+struct node {
+    int info;
+    struct node *next;
+};
+
+struct node *ptr, *newptr, *head = NULL;
+
+struct node* getnode() {
+    struct node *np;
+    np = (struct node *)malloc(sizeof(struct node));
+    printf("Enter the value to store: ");
+    scanf("%d", &np->info);
+    np->next = NULL;
+    return np;
+};
+
+void create() {
+    char choice;
+    struct node *last;
+    do {
+        newptr = getnode();
+        if(head == NULL) head = newptr;
+        else last->next = newptr;
+        last = newptr;
+        fflush(stdin);
+        printf("Want to add more (y or n): ");
+        scanf("%c", &choice);
+    } while(choice == 'Y' || choice == 'y');
+    printf("\n Created a linked list successfully \n");
+}
+
+void insert() {
+    int choice;
+    while(1) {
+        system("cls");
+        printf("\t\t*********** Insertion Menu ***************");
+        printf("\n\t\t1. At front \n\t\t2. At end \n\t\t3. At anywhere \n\t\t4. Back to main menu \n\t\t  Enter your choice: ");
+        scanf("%d", &choice);
+        switch(choice) {
+            case 1:
+                {
+                    newptr = getnode();
+                    newptr->next = head;
+                    head = newptr;
+                    printf("\n\t\tNode inserted at front! \n press any key to continue");
+                    getch();
+                }
+                break;
+            case 2:
+                {
+                    newptr = getnode();
+                    ptr = head;
+                    while(ptr->next != NULL) ptr = ptr->next;
+                    ptr->next = newptr;
+                    printf("\n\t\tNode inserted at end! \n press any key to continue");
+                    getch();
+                }
+                break;
+            case 3:
+                {
+                    int key;
+                    printf("Enter the key after which you want to add node: ");
+                    scanf("%d", &key);
+                    newptr = getnode();
+                    ptr = head;
+                    while(ptr != NULL && ptr->info != key) ptr = ptr->next;
+                    if(ptr == NULL) printf("Key you entered doesnot exist!!\n");
+                    else {
+                        newptr->next = ptr->next;
+                        ptr->next = newptr;
+                    }
+                    printf("\n\t\tNode inserted after key %d! \n press any key to continue", key);
+                    getch();
+                }
+                break;
+            case 4:
+                return;
+                break;
+            default:
+                printf("No such choice!!");
+                getch();
+        }
+    }
+}
+
+void Delete() {
+    int choice;
+    while(1) {
+        system("cls");
+        printf("\n\t\t1. At front \n\t\t2. At end \n\t\t3. At anywhere \n\t\t4. Exit \n\t\t  Enter your choice: ");
+        scanf("%d", &choice);
+        switch(choice) {
+            case 1:
+                {
+                    ptr = head;
+                    head = head->next;
+                    free(ptr);
+                    printf("\n\t\tNode deleted at front! \n press any key to continue");
+                    getch();
+                }
+                break;
+            case 2:
+                {
+                    struct node *prevptr;
+                    ptr = head;
+                    while(ptr->next != NULL) {
+                            prevptr = ptr;
+                            ptr = ptr->next;
+                    }
+                    prevptr->next = NULL;
+                    free(ptr);
+                    printf("\n\t\tNode deleted at end! \n press any key to continue");
+                    getch();
+                }
+                break;
+            case 3:
+                {
+                    int key;
+                    struct node *prevptr;
+                    printf("Enter the key for node which you want to delete node: ");
+                    scanf("%d", &key);
+                    ptr = head;
+                    while(ptr != NULL && ptr->info != key) {
+                        prevptr = ptr;
+                        ptr = ptr->next;
+                    }
+                    if(ptr == NULL) printf("Key you entered doesnot exist!!\n");
+                    else {
+                        prevptr->next = ptr->next;
+                        free(ptr);
+                    }
+                    printf("\n\t\tNode deleted with key %d! \n press any key to continue", key);
+                    getch();
+                }
+                break;
+            case 4:
+                return;
+            default:
+                printf("No such choice!!");
+                getch();
+        }
+    }
+}
+
+void display() {
+    system("cls");
+    if(head == NULL) printf("Linked List is empty!!\n");
+    else {
+        ptr = head;
+        while(ptr != NULL) {
+            printf("\t\t%d \n", ptr->info);
+            ptr = ptr->next;
+        }
+    }
+    printf("\t\tEnter any key to continue!");
+    getch();
+}
+
+int main() {
+    int choice;
+    create();
+    while(1){
+        system("cls");
+        printf("\t\t************** Singly Linked List ***************");
+        printf("\n\t\t1. Insert \n\t\t2. Delete \n\t\t3. Display \n\t\t4. Exit \n\t\t  Enter your choice: ");
+        scanf("%d", &choice);
+        switch(choice) {
+            case 1:
+                insert();
+                break;
+            case 2:
+                Delete();
+                break;
+            case 3:
+                display();
+                break;
+            case 4:
+                exit(0);
+            default:
+                printf("No such choice!!");
+                getch();
+        }
+    }
+}