#include <stdio.h> #include <stdlib.h> #include <conio.h> #include <string.h> #define MAX 30 struct EMP { int empno; char empName[MAX]; char designation[MAX]; struct EMP *next; }; /*********************************************************************/ /* Function to insert a node at the front of the linked list. */ /* front: front pointer, id: employee ID, name: employee name */ /* desg: Employee designation */ /* Returns the new front pointer. */ /*********************************************************************/ struct EMP* insert(struct EMP *front, int id, char name[], char desg[]) { struct EMP *newnode; newnode = (struct EMP*) malloc(sizeof(struct EMP)); if (newnode == NULL) { printf("\nAllocation failed\n"); exit(2); } newnode->empno = id; strcpy(newnode->empName, name); strcpy(newnode->designation, desg); newnode->next = front; front = newnode; return(front); } /*End of insert() */ /* Function to display a node in a linked list */ void printNode(struct EMP *p) { printf("\nEmployee Details...\n"); printf("\nEmp No : %d", p->empno); printf("\nName : %s", p->empName); printf("\nDesignation : %s\n", p->designation); printf("-------------------------------------\n"); } /*End of printNode() */ /* ********************************************************/ /* Function to deleteNode a node based on employee number */ /* front: front pointer, id: Key value */ /* Returns: the modified list. */ /* ********************************************************/ struct EMP* deleteNode(struct EMP *front, int id) { struct EMP *ptr; struct EMP *bptr; /* bptr is pointing to the node behind ptr */ if (front->empno == id) { ptr = front; printf("\nNode deleted:"); printNode(front); front = front->next; free(ptr); return(front); } for(ptr=front->next, bptr=front; ptr!=NULL; ptr=ptr->next, bptr=bptr->next) { if (ptr->empno == id) { printf("\nNode deleted:"); printNode(ptr); bptr->next = ptr->next; free(ptr); return(front); } } printf("\nEmployee Number %d not found ", id); return(front); } /*End of deleteNode() */ /*****************************************************************/ /* Function to search the nodes in a linear fashion based emp ID */ /* front: front pointer, key: key ID. */ /*****************************************************************/ void search(struct EMP *front, int key) { struct EMP *ptr; for (ptr = front; ptr != NULL; ptr = ptr -> next) { if (ptr->empno == key) { printf("\nKey found:"); printNode(ptr); return; } } printf("\nEmployee Number %d not found ", key); } /*End of search() */ /* Function to display the linked list */ void display(struct EMP *front) { struct EMP *ptr; for (ptr = front; ptr != NULL; ptr = ptr->next) { printNode(ptr); } } /*End of display() */ /* Function to display the menu of operations on a linked list */ void menu() { printf("---------------------------------------------\n"); printf("Press 1 to INSERT a node into the list \n"); printf("Press 2 to DELETE a node from the list \n"); printf("Press 3 to DISPLAY the list \n"); printf("Press 4 to SEARCH the list \n"); printf("Press 5 to EXIT \n"); printf("---------------------------------------------\n"); } /*End of menu() */ /* Function to select the option */ char option() { char choice; printf("\n\n>> Enter your choice: "); switch(choice=getche()) { case '1': case '2': case '3': case '4': case '5': return(choice); default : printf("\nInvalid choice."); } return choice; } /*End of option() */ /* The main() program begins */ void main() { struct EMP *linkList; char name[21], desig[51]; char choice; int eno; linkList = NULL; printf("\nWelcome to demonstration of singly linked list\n"); menu(); /*Function call */ do { choice = option(); /*to choose oeration to be performed */ switch(choice) { case '1': printf("\nEnter the Employee Number : "); scanf("%d", &eno); printf("Enter the Employee name : "); fflush(stdin); gets(name); printf("Enter the Employee Designation : "); gets(desig); linkList = insert(linkList, eno, name, desig); break; case '2': printf("\n\nEnter the employee number to be deleted: "); scanf("%d", &eno); linkList = deleteNode(linkList, eno); break; case '3': if (linkList == NULL) { printf("\nList empty."); break; } display(linkList); break; case '4': printf("\n\nEnter the employee number to be searched: "); scanf("%d", &eno); search(linkList, eno); break; case '5': break; } } while (choice != '5'); }
Welcome to demonstration of singly linked list --------------------------------------------- Press 1 to INSERT a node into the list Press 2 to DELETE a node from the list Press 3 to DISPLAY the list Press 4 to SEARCH the list Press 5 to EXIT --------------------------------------------- >> Enter your choice: 1 Enter the Employee Number : 1234 Enter the Employee name : Keerthi Enter the Employee Designation : Engineer >> Enter your choice: 1 Enter the Employee Number : 2345 Enter the Employee name : Srinivasan Enter the Employee Designation : Specilist >> Enter your choice: 1 Enter the Employee Number : 4567 Enter the Employee name : Annapoorna Enter the Employee Designation : Project Manager >> Enter your choice: 3 Employee Details... Emp No : 4567 Name : Annapoorna Designation : Project Manager ------------------------------------- Employee Details... Emp No : 2345 Name : Srinivasan Designation : Specilist ------------------------------------- Employee Details... Emp No : 1234 Name : Keerthi Designation : Engineer ------------------------------------- >> Enter your choice: 2 Enter the employee number to be deleted: 2345 Node deleted: Employee Details... Emp No : 2345 Name : Srinivasan Designation : Specilist ------------------------------------- >> Enter your choice: 3 Employee Details... Emp No : 4567 Name : Annapoorna Designation : Project Manager ------------------------------------- Employee Details... Emp No : 1234 Name : Keerthi Designation : Engineer ------------------------------------- >> Enter your choice: 4 Enter the employee number to be searched: 2345 Employee Number 2345 not found >> Enter your choice: 5
