Project - phone book (Doubly)

/*Phone Book*/

#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,*currentprev,*temp;

    current = start;

    if(start == NULL)
        start = newnode;

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

        if(strcmp(newnode,current)>0){
            current->next = newnode;
            newnode -> prev = current;
        }

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

    else{
        while(current!=NULL){
            if(strcmp(newnode,current)<0)
                break;
            if(current->next==NULL)
                temp=current;
            current = current->next;
        }

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

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

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

}


int checkernum(struct node *newnode)
{
    int i=0;
    struct node *current;
    current=start;
    while(current!=NULL){
        if(strcmp(current->number,newnode->number)==0){
            i++;
            break;
        }
        current=current->next;
    }
    return i;
}


int checkername(struct node *newnode)
{
    int i=0;
    struct node *current;
    current=start;
    while(current!=NULL){
        if(strcmp(current->name,newnode->name)==0){
            i++;
            break;
        }
        current=current->next;
    }
    return i;
}

void insert()
{
    struct node *newnode,*current;
    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);

    int i=checkername(newnode);
    int j=checkernum(newnode);
    if(i==0 && j==0){
        sort(newnode);
        printf("\n*save successful*\n");
    }
    else{
        printf("\nContact Exist, can't save it\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);

    char n;

    printf("1. Change name\n");
    printf("2. Skip\n");

    getchar();
    scanf("%c",&n);

    if(n == '1'){
        printf("name : ");
        getchar();
        scanf("%[^\n]",current->name);
    }

    printf("1. Change number\n");
    printf("2. Skip\n");

    getchar();
    scanf("%c",&n);

    if(n == '1'){
        printf("number: ");
        getchar();
        scanf("%s",current->number);
    }

    printf("1. Change about\n");
    printf("2. Skip\n");

    getchar();
    scanf("%c",&n);

    if(n == '1'){
        printf("about : ");
        getchar();
        scanf("%[^\n]",current->about);
    }

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

    sort(current);

}


void byname()
{
    struct node *current;

    if(start==NULL){
        printf("\nNo Contact saved for search\n");
        return;
    }

    char str[100];
    printf("Enter name for search : ");
    getchar();
    scanf("%[^\n]",str);
    current = start;

    int i=0;
    char n;

    while(current!=NULL){
        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;
        }

        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 : ");

        getchar();
        scanf("%c",&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;

    if(start==NULL){
        printf("\nNo Contact saved for search\n");
        return;
    }

    char str[100];

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

    current = start;

    int i=0;
    char n;

    while(current!=NULL){
        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;
        }
        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 : ");

        getchar();
        scanf("%c",&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(current!=NULL){
        count++;
        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;
        current = start;
        int i=0;
        while(current!=NULL){
            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");

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


void home()
{
    char n;
    printf("\nChose an option : ");
    getchar();
    scanf("%c",&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();
    else
        return;
}


int main()
{
    char n[100],x[100];
    strcpy(x,"12345");
    printf("\n***PHONE BOOK***\n\n");
    while(1){
        printf("\nEnter PIN: ");
        scanf("%s",n);

        if(strcmp(n,x)!=0){
            printf("Wrong password\n");
            continue;
        }
        printf("Password matched - WELCOME\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;
}