Question

Programming C: Write a program for a Rolodex of contact information (e.g., name, phone number, email) implemented as a linked list. The program will ask the user to enter a new contact information, retrieve/print a person’s contact information, and to delete a person. It will maintain the linked list in alphabetical order by last name. It will also allow the user to search for a person’s contact information by last name. Assume that all last names are unique.

Answer 1

//C program

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

typedef struct node{
   char firstName[20];
   char lastName[20];
   int phoneNumber;
   char email[25];
   struct node*next;
}Node;

void Insert(Node** head, Node* new_node)
{
Node* current;
  
if (*head == NULL || strcmp((*head)->lastName,new_node->lastName)>0)
{
new_node->next = *head;
*head = new_node;
}
else
{

current = *head;
while (current->next!=NULL && strcmp(current->lastName,new_node->lastName)<0)
{
current = current->next;
}
new_node->next = current->next;
current->next = new_node;
}
}

void print(char *name,Node*head) {
   while(head &&strcmp(head->lastName,name)!=0)head = head->next;
   if(!head){
       printf("Not found in list \n");
       return;
   }
   printf("Name : %s %s \n",head->firstName,head->lastName);
   printf("Phone Number : %d\n",head->phoneNumber);
   printf("Email : %s\n\n",head->email);
  
}
void deletion(Node**head,char*name){
   Node* temp = *head, *prev;
if (temp != NULL && strcmp(temp->lastName,name)==0)
{
*head = temp->next;
free(temp);
return;
}
while (temp != NULL && strcmp(temp->lastName,name)!=0)
{
prev = temp;
temp = temp->next;
}

if (temp == NULL) return;
prev->next = temp->next;
  
free(temp);
}

int main(){
   Node*head=NULL;
   int choice;
   char first[20],last[20],email[25];
   int phone;
  
   do{
       printf("\n1:insert\n2:print\n3:Delete\n4:Quit\nEnter choice : ");
       scanf("%d",&choice);
       switch(choice){
           case 1:{
               printf("Enter first name : ");
               scanf("%s",first);
               printf("Enter last name : ");
               scanf("%s",last);
               printf("Enter phone number : ");
               scanf("%d",&phone);
               printf("Enter Email : ");
               scanf("%s",email);
               Node*newNode = (Node*)malloc(sizeof(Node));
               strcpy(newNode->firstName, first);
               strcpy(newNode->lastName, last);
               newNode->phoneNumber= phone;
               strcpy(newNode->email, email);
               Insert(&head,newNode);
              
               break;
           }
           case 2:{
               printf("Enter last name : ");
               scanf("%s",last);
               print(last,head);
               break;
           }
           case 3:{
               printf("Enter last name : ");
               scanf("%s",last);
               deletion(&head,last);
               break;
           }
           case 4:{
               printf("\nthank you!\n");
               break;
           }
           default:{
               printf("Invalid choice\n");
               break;
           }
       }
   }while(choice!=4);
  
   return 0;
}

//sample output