Updated Phonebook Code

#include <stdio.h>
#include <string.h>
#include <stdlib.h>
struct node
{
    char number[100];
    char gmail[100];
    char name[100];
    struct node *prev, *next;
} *head = NULL;

void insert()
{
    char number[100];
    char gmail[100];
    char name[100];
    char ans;
    do
    {
        struct node *p;
        p = (struct node *)malloc(sizeof(struct node));
        printf("Enter The Name of The Contact: ");
        scanf("%[^\n]", name);
        fflush(stdin);
        strcpy(p->name, name);
        printf("Enter The Phone Number    :\t");
        scanf("%[^\n]", number);
        fflush(stdin);

        while (strlen(number) != 10)
        {
            printf("ENTER A VALID 10 DIGIT NUMBER  :\t");
            scanf("%[^\n]", number);
            fflush(stdin);
        }
        strcpy(p->number, number);
        printf("Enter The G-Mail ID  :\t");
        scanf("%[^\n]", gmail);
        strcpy(p->gmail, gmail);
        fflush(stdin);

        if (head == NULL)
        {
            p->next = NULL;
            p->prev = NULL;
            head = p;
        }
        else
        {
            struct node *tmp = head;
            while (tmp->next != NULL)
            {
                tmp = tmp->next;
            }
            p->next = NULL;
            p->prev = tmp;
            tmp->next = p;
        }
        printf("Do You Want To Continue?????????\n");
        scanf("%c", &ans);
        fflush(stdin);
    } while (ans == 'y');
}
void display()
{
    struct node *tmp = head;
    while (tmp != NULL)
    {
        printf("\nNAME  ::  %s", tmp->name);
        printf("\nNUMBER::  +91-%s", tmp->number);
        printf("\nG-MAIL::  %s\n", tmp->gmail);
        tmp = tmp->next;
    }
}
void sort()
{
    struct node *i, *j;
    int temp;
    char a[100], b[100], c[100];
    for (i = head; i->next != NULL; i = i->next)
    {
        for (j = i->next; j != NULL; j = j->next)
        {
            temp = strcmp(i->name, j->name);
            if (temp > 0)
            {
                strcpy(a, i->name);
                strcpy(i->name, j->name);
                strcpy(j->name, a);
                strcpy(b, i->number);
                strcpy(i->number, j->number);
                strcpy(j->number, b);
                strcpy(c, i->gmail);
                strcpy(i->gmail, j->gmail);
                strcpy(j->gmail, c);
            }
        }
    }
}
void deletecontact()
{
    char s[100];
    printf("Enter the Name of the Contact You Wish to Delete\n");
    scanf("%[^\n]", s);
    fflush(stdin);
    int c = 0;
    struct node *tmp = head;
    while (tmp != NULL)
    {
        if (strcmp(s, tmp->name) == 0)
        {
            c = 1;
            break;
        }
        else
        {
            c = 2;
        }
        tmp = tmp->next;
    }
    if (!tmp)
    {
        printf("CONTACT NOT FOUND\n");
        return;
    }
    if (c == 1 && tmp != head && tmp->next != NULL)
    {
        tmp->prev->next = tmp->next;
        tmp->next->prev = tmp->prev;
        free(tmp);
        printf("YOUR CONTACT IS SUCCESSFULLY DELETED\n\n");
    }
    if (tmp == head)
    {
        head = head->next;
        head->prev = NULL;
        free(tmp);
        printf("YOUR CONTACT IS SUCCESSFULLY DELETED\n\n");
    }
    if (tmp->next == NULL)
    {
        tmp->prev->next = NULL;
        tmp->prev = NULL;
        free(tmp);
        printf("YOUR CONTACT IS SUCCESSFULLY DELETED\n\n");
    }
}
void deletesamename()
{
    struct node *tmp1 = head;
    int n = 0;
    while (tmp1 != NULL && tmp1->next != NULL)
    {
        struct node *tmp2 = tmp1;
        while (tmp2->next != NULL)
        {
            if (strcmp(tmp1->name, tmp2->next->name) == 0)
            {
                struct node *dup = tmp2->next;
                tmp2->next = tmp2->next->next;
                free(dup);
                n++;
            }
            else
            {
                tmp2 = tmp2->next;
            }
        }
        tmp1 = tmp1->next;
    }
    if (!n)
        printf("Same Names Not Found\n");
    else
        display();
}
void deletesamegmail()
{
    struct node *tmp1 = head;
    int n = 0;
    while (tmp1 != NULL && tmp1->next != NULL)
    {
        struct node *tmp2 = tmp1;
        while (tmp2->next != NULL)
        {
            if (strcmp(tmp1->gmail, tmp2->next->gmail) == 0)
            {
                struct node *dup = tmp2->next;
                tmp2->next = tmp2->next->next;
                free(dup);
                n++;
            }
            else
            {
                tmp2 = tmp2->next;
            }
        }
        tmp1 = tmp1->next;
    }
    if (!n)
        printf("Same G-Mail IDs Not Found\n");
    else
        display();
}
void deletesamenumber()
{
    struct node *tmp1 = head;
    int n = 0;
    while (tmp1 != NULL && tmp1->next != NULL)
    {
        struct node *tmp2 = tmp1;
        while (tmp2->next != NULL)
        {
            if (strcmp(tmp1->number, tmp2->number) == 0)
            {
                struct node *dup = tmp2->next;
                tmp2->next = tmp2->next->next;
                free(dup);
                n++;
            }
            else
            {
                tmp2 = tmp2->next;
            }
        }
        tmp1 = tmp1->next;
    }
    if (!n)
        printf("Same Numbers Not Found\n");
    else
        display();
}
void searchbyname(char *na)
{
    struct node *tmp = head;
    while (tmp != NULL)
    {
        if (strcmp(na, tmp->name) == 0)
        {
            printf("NAME FOUND\n");
            printf("CONTACT DETAILS ARE BELOW:\n");
            printf("\n\nNAME  ::\t%s", tmp->name);
            printf("\nNUMBER::\t+91-%s", tmp->number);
            printf("\nG-MAIL::\t%s", tmp->gmail);
        }
        tmp = tmp->next;
    }
    if (!tmp)
        printf("CONTACT NOT FOUND\n");
}
void searchbynumber(char *num)
{
    struct node *tmp = head;
    while (tmp != NULL)
    {
        if (strcmp(num, tmp->number) == 0)
        {
            printf("NUMBER FOUND\n");
            printf("CONTACT DETAILS ARE BELOW:\n");
            printf("\n\nNAME  ::\t%s", tmp->name);
            printf("\nNUMBER::\t+91-%s", tmp->number);
            printf("\nG-MAIL::\t%s", tmp->gmail);
        }
        tmp = tmp->next;
    }
    if (!tmp)
        printf("CONTACT NOT FOUND\n");
}
void searchbygmail(char *gm)
{
    struct node *tmp = head;
    while (tmp != NULL)
    {
        if (strcmp(gm, tmp->gmail) == 0)
        {
            printf("G-MAIL FOUND\n");
            printf("CONTACT DETAILS ARE BELOW:\n");
            printf("\n\nNAME  ::\t%s", tmp->name);
            printf("\nNUMBER::\t+91-%s", tmp->number);
            printf("\nG-MAIL::\t%s", tmp->gmail);
        }
        tmp = tmp->next;
    }
    if (!tmp)
        printf("CONTACT NOT FOUND\n");
}
void update()
{
    char n[100];
    char ans;
    int c;
    struct node *tmp = head;
    printf("\nEnter the Name of the Contact that You Wish to Update\n");
    scanf("%[^\n]", n);
    fflush(stdin);
    while (tmp != NULL)
    {
        if (strcmp(n, tmp->name) == 0)
        {

            do
            {
                printf("\nWHAT DO YOU WANT TO UPDATE?\n1.NAME\n2.PHONE NUMBER\n3.G-MAIL\n");
                scanf("%d", &c);
                fflush(stdin);
                switch (c)
                {
                case 1:
                    printf("Enter The New Name:\n");
                    scanf("%[^\n]", tmp->name);
                    fflush(stdin);
                    break;
                case 2:
                    printf("Enter the New Phone Number:\n");
                    scanf("%[^\n]", tmp->number);
                    fflush(stdin);
                    while (strlen(tmp->number) != 10)
                    {
                        printf("ENTER A VALID NUMBER!  :\n");
                        scanf("%[^\n]", tmp->number);
                        fflush(stdin);
                    }
                    break;
                case 3:
                    printf("Enter The New G-Mail ID:\n");
                    scanf("%[^\n]", tmp->gmail);
                    fflush(stdin);
                    break;
                }
                printf("Do You Wish To Continue Updating?\n");
                scanf("%c", &ans);
                fflush(stdin);
            } while (ans == 'y');
        }
        tmp = tmp->next;
    }
}
int main()
{
    char n[100];
    char nam[100];
    char name[100];
    char number[100];
    char gmail[100];
    char ans;
    int ch, a;
    printf("**************                                PHONE BOOK                          ********************\n");
    printf("\n\nWHAT IS YOUR NAME?\n");
    scanf("%[^\n]", name);
    fflush(stdin);
    printf("\n\n!!!!!!!!!!!!!!!!!!!!!!!   Welcome %s  !!!!!!!!!!!!!!!!!!!!!!! \n", name);
    printf("\n\n\nLET'S CREATE OUR PHONEBOOK \n\n");
    insert();
    sort();
    fflush(stdin);
    while (1)
    {
        printf("\n\n\n\n1) DISPLAY YOUR PHONE BOOK\n2) INSERT NEW CONTACT\n3) UPDATE DETAILS ON EXISTING CONTACT\n4) DELETE CONTACT\n5) DELETE SAME NAME IN PHONEBOOK\n6) DELETE SAME NUMBERS IN PHONEBOOK\n7) DELETE SAME GMAIL-ID IN PHONEBOOK\n8) SEARCH\n");
        scanf("%d", &ch);
        fflush(stdin);
        switch (ch)
        {
        case 1:
            display();
            break;

        case 2:
            insert();
            sort();
            break;
        case 3:
            update();
            sort();
            break;
        case 4:
            deletecontact();
            break;

        case 5:
            deletesamename();
            break;

        case 6:
            deletesamenumber();
            break;
        case 8:
            do
            {
                printf("1.SEARCH BY NAME\n2.SEARCH BY NUMBER\n3.SEARCH BY GMAIL\n");
                scanf("%d", &a);
                fflush(stdin);
                switch (a)
                {
                case 1:
                    printf("\nENTER THE NAME TO BE SEARCHED\n");
                    scanf("%[^\n]", name);
                    fflush(stdin);
                    searchbyname(name);
                    break;
                case 2:
                    printf("ENTER THE NUMBER TO BE SEARCHED\n");
                    scanf("%[^\n]", number);
                    fflush(stdin);
                    searchbynumber(number);
                    break;
                case 3:
                    printf("ENTER THE GMAIL ID TO BE SEARCHED\n");
                    scanf("%[^\n]", gmail);
                    fflush(stdin);
                    searchbygmail(gmail);
                    break;
                default:
                    printf("\nNO PROPER INPUT GIVEN.....\n");
                }
                printf("\nDO YOU WANT TO CONTINUE SEARCHING?????????\n");
                scanf("%c", &ans);
                fflush(stdin);
            } while (ans == 'y');

            break;
        case 7:
            deletesamegmail();
            break;
        default:
            printf("\nENTER A VALID INPUT\n");
            break;
        }

        printf("\n\nDO YOU WANT TO CONTINUE OPERATIONS?????????\n");
        scanf("%c", &ans);
        if (ans != 'y')
            break;
        fflush(stdin);
    }
}