phonebook project base

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

struct node{
    char name[100];
    char number[20];
    char about[1000];
    struct node *next;
    struct node *prev;
}*start=NULL;


void sort(struct node *newnode)
{
    struct node *current;

    current = start;

    if(start == NULL)
        start = newnode;

    else if(start->next == NULL){

        if(current->name[0] <= newnode->name[0]){
            current->next = newnode;
            newnode -> prev = current;
        }

        else{
            newnode->next = current;
            current->prev = newnode;
            start = newnode;
        }
    }

    else{
        while(current->name[0] <= newnode->name[0]){
            if(current->next == NULL)
                break;
            current = current->next;
        }

        if(current == start){
            newnode->next = current;
            current->prev = newnode;
            start = newnode;
        }

        else if(current->next == NULL){
            current->next = newnode;
            newnode->prev = current;
        }

        else{
             struct node *currentprev;
            currentprev = current->prev;
            currentprev->next = newnode;
            newnode->prev = currentprev;
            newnode->next = current;
            current->prev = newnode;
        }
    }

}


void insert()
{
    struct node *newnode,*current,*currentprev;
    newnode=(struct node*)malloc(sizeof(struct node));
    newnode->next=NULL;
    newnode->prev=NULL;

    printf("name : ");
    getchar();
    scanf("%[^\n]",newnode->name);

    printf("number: ");
    getchar();
    scanf("%s",newnode->number);

    printf("about : ");
    getchar();
    scanf("%[^\n]",newnode->about);

    sort(newnode);

    printf("\n*save successful*\n");
}


void del(struct node *current)
{
    if(current == start)
        start = current->next;

    else if(current->next == NULL)
        (current->prev)->next = NULL;

    else{
        struct node *currentprev, *currentnext;
        currentprev = current->prev;
        currentnext = current->next;
        currentprev->next = currentnext;
        currentnext->prev = currentprev;
    }
}


void edit(struct node *current)
{
    del(current);

    int n;

    printf("1. Change name\n");
    printf("2. Skip\n");
    scanf("%d",&n);
    if(n == 1){
        printf("name : ");
        getchar();
        scanf("%[^\n]",current->name);
    }

    printf("1. Change number\n");
    printf("2. Skip\n");
    scanf("%d",&n);
    if(n == 1){
        printf("number: ");
        getchar();
        scanf("%s",current->number);
    }

    printf("1. Change about\n");
    printf("2. Skip\n");
    scanf("%d",&n);
    if(n == 1){
        printf("about : ");
        getchar();
        scanf("%[^\n]",current->about);
    }

    current->next = NULL;
    current->prev = NULL;

    sort(current);

}


void byname()
{
    struct node *current;
    char str[100];
    printf("Enter name for search : ");
    getchar();
    scanf("%[^\n]",str);
    current = start;
    int i=0, n;

    while(1){
        if(strcmp(current->name,str)==0){
            printf("\nName found\n");
            printf("name : %s\n",current->name);
            printf("Number : %s\n",current->number);
            printf("about : %s\n",current->about);
            printf("\n");
            i++;
            break;
        }

        if(current->next == NULL)
            break;

        current = current->next;
    }

    if(i==0)
        printf("\nNot Found\n");

    else{
        printf("1. Edit\n");
        printf("2. Delete\n");
        printf("0. Home\n");
        printf("Chose an option : ");
        scanf("%d",&n);

        if(n == 1){
            edit(current);
            printf("\n*edit successful*\n");
        }
        else if(n == 2){
            del(current);
            printf("\n*Delete successful*\n");
        }
        else if(n == 0)
            return;
    }

}


void bynumber()
{
    struct node *current;
    char str[100];

    printf("Enter number for search : ");
    getchar();
    scanf("%[^\n]",str);

    current = start;
    int i=0, n;

    while(1){
        if(strcmp(current->number,str)==0){
            printf("\nNumber found\n");
            printf("name : %s\n",current->name);
            printf("Number : %s\n",current->number);
            printf("about : %s\n",current->about);
            printf("\n");
            i++;
            break;
        }

        if(current->next == NULL)
            break;

        current = current->next;
    }

    if(i==0)
        printf("\nNot Found\n");

    else{
        printf("1. Edit\n");
        printf("2. Delete\n");
        printf("0. Home\n");
        printf("Chose an option : ");
        scanf("%d",&n);

        if(n == 1)
            edit(current);
        else if(n == 2)
            del(current);
        else if(n == 0)
            return;
    }

}


void count()
{
    struct node *current;
    int count = 0;
    current = start;

    while(1){
        count++;
        if(current->next == NULL)
            break;
        current = current->next;
    }
    printf("\nTotal contacts %d\n",count);
}


void displayall()
{

    if(start == NULL)
        printf("\nNo contact for display\n");

    else{
        count();
        struct node *current,*currentprev;
        current = start;
        int i=0;
        while(1){
            i++;
            printf("\nContact no %d :-\n",i);
            printf("name : %s\n",current->name);
            printf("Number : %s\n",current->number);
            printf("about : %s\n",current->about);
            printf("\n");

            if(current->next == NULL)
                break;

            current = current->next;
        }
    }
    printf("\n");
}


void home()
{
    int n;
    printf("\nChose an option : ");
    scanf("%d",&n);

    if(n==0)
        exit(0);

    else if(n==1)
        insert();

    else if(n==2)
        displayall();

    else if(n==3)
        byname();

    else if(n==4)
        bynumber();

}


int main()
{
    int n;

    while(1){
        printf("\n***HOME***\n\n");
        printf("1. Save a new contact\n");
        printf("2. Show all contact\n");
        printf("3. Search by name\n");
        printf("4. Search by number\n");
        printf("0. exit\n");
        home();
    }
    return 0;
}