BEN10, i explicitly let know that actually it returns pointer to my struct type.
Okay, i have worked a little on my code, and decided to implement this linked listed in a better way, and more natural as it should be.
So if u would like just take a quick look, say if something is wrong. Thank you.
Below is the working code of linked list implementation:
Code:#include <stdio.h> #include <stdlib.h> #define snapd(expr) printf(#expr " = %d\n", expr); #define snapd(expr) printf(#expr " = %d\n", expr); /* Function prototypes */ void printlist(struct node *list); void find(struct node *list, int value); struct node *removenode(struct node *list, int value); struct node *insert(struct node *list, int value); /* Node definition */ struct node { int data; struct node *ptr; }; /* This function prints out the contents of the linked list */ void printlist(struct node *list) { if (list == NULL) { printf("The list is empty!\n"); return; } while (list->ptr != NULL) { printf("%d\n", list->data); list = list->ptr; } if (list->ptr == NULL) { printf("%d\n", list->data); } } void find(struct node *list, int value) { struct node *previous = list; if (list->data == value) { printf("The element %d have been at the beginning of the list before %d\n", value, list->ptr->data); return; } while (list->ptr != NULL) { if (list->data == value && list->ptr != NULL) { printf("The element %d have been found between %d and %d\n", value, previous->data, list->ptr->data); return; } previous = list; list = list->ptr; } if (list->data == value) { printf("The element %d have been found at the end of the list after %d\n", value, previous->data); return; } printf("The element %d is not found in the list...\n"); } /* This function inserts the value in the appropriate position in the linked list */ struct node *insert(struct node *list, int value) { struct node *newnode, *previous = list, *first = list; //if the list is empty, add the first element if (list == NULL) { newnode = (struct node *)malloc(sizeof(struct node)); newnode->data = value; newnode->ptr = NULL; return newnode; } // Add value before the first element if (value < list->data) { snapd(list->data); newnode = (struct node *)malloc(sizeof(struct node)); newnode->data = value; newnode->ptr = list; return newnode; } if (value == list->data) { printf("There is already element %d in the list!\n", value); return first; } // Add the value in the middle of the list while (list->ptr != NULL) { if (value < list->data) { newnode = (struct node *)malloc(sizeof(struct node)); newnode->data = value; newnode->ptr = list; previous->ptr = newnode; return first; } if (value == list->data) { printf("There is already element %d in the list!\n", value); return first; } previous = list; list = list->ptr; } if (list->ptr == NULL && value == list->data) { printf("There is already element %d in the list!\n", value); return first; } // Add after the last element of the list if (list->ptr == NULL && value > list->data) { newnode = (struct node *)malloc(sizeof(struct node)); newnode->data = value; newnode->ptr = NULL; list->ptr = newnode; return first; } // Add before the last element of the list if (list->ptr == NULL && value < list->data) { newnode = (struct node *)malloc(sizeof(struct node)); newnode->data = value; newnode->ptr = list; previous->ptr = newnode; return first; } } /* This function deletes the specified node */ struct node *removenode(struct node *list, int value) { struct node *first = list, *previous = list; //handle the empty list if (list == NULL) { printf("The list is already empty!\n"); return first; } //handle the deletion of single element in the list if (list->ptr == NULL && list->data == value) { free(list); return NULL; } //handle the deletion of first element if (list->ptr != NULL && list->data == value) { first = list->ptr; list->ptr = NULL; free(list); return first; } while (list->ptr != NULL) { if (list->data == value) { previous->ptr = list->ptr; free(list); return first; } previous = list; list = list->ptr; } // handle the deletion of the last element in the list if (list->ptr == NULL && list->data == value) { previous->ptr = NULL; free(list); return first; } //the value to be removed havent been found in the list printf("There is no %d in the list!\n", value); return first; } void main (int argc, char *argv[]) { struct node *mylist = NULL; int value; int command; printf("Available commands:\n"); printf("1 - add new element:\n"); printf("2 - remove element:\n"); printf("3 - print the list:\n"); printf("4 - find a value in a list:\n"); printf("0 - quit program:\n"); printf("Enter command: "); for(;;) { scanf("%d", &command); switch (command) { case 1: printf("Enter the value to be added in the list: "); scanf("%d", &value); mylist = insert(mylist,value); printf("Enter the next command "); break; case 2: printf("Enter the value to be removed: "); scanf("%d", &value); mylist = removenode(mylist, value); printf("Enter the next command "); break; case 3: printf("Linked list values:\n"); printf("===================\n"); printlist(mylist); printf("===================\n"); printf("Enter the next command "); break; case 4: printf("Enter the value to be searched for: "); scanf("%d", &value); find(mylist, value); printf("Enter the next command "); break; case 0: return; break; default: printf("wrong command!\n"); printf("Available commands:\n"); printf("1 - add new element:\n"); printf("2 - remove element:\n"); printf("3 - print the list:\n"); printf("4 - find a value in a list:\n"); printf("0 - quit program:\n"); printf("Enter command: "); break; } } }
