Step 11: Prevent Phonebook Overflow

Problem Statement

Add the permanent phonebook-capacity guard to add_contact(). Before starting a new insertion, check whether contact_count has reached the maximum capacity of 100. When the phonebook is full, print Phonebook Full and leave the existing records unchanged. Retain every previously implemented ID reading, validation, duplicate detection, name input, phone validation, storage, and counter-update behavior.

Input Format

One or more complete Add Contact operations beginning with menu choice 1, followed by ID, name, and phone values. The sequence may contain enough successful additions to fill the phonebook, and ends with menu choice 0.

Output Format

Successful insertions behave exactly as in Task 10. Any Add operation attempted when contact_count is 100 prints Phonebook Full and does not read or store another contact.

Constraints

The phonebook capacity is exactly 100. Valid IDs are positive and unique. Phone length is 1 to 14 characters. No insertion may occur when contact_count is already 100.

Sample Input

Sample Output

Contact Book Ready.
Phonebook Capacity: 100
Contacts: 0
Modules Ready.
Menu:
Add
ID: 101
Valid ID
Name: Alice
Phone: 1234567890
Valid Phone
Contact Added
Menu:
Add
Phonebook Full
Menu:
Exit

Explanation

The capacity guard prevents writes beyond the phonebook array. Because the project supports exactly 100 contacts, the guard must run before reading or storing a new record once contact_count reaches 100.

Starter Code

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

struct Contact {
    int id;
    char name[50];
    char phone[15];
};

struct Contact phonebook[100];
int contact_count = 0;

void add_contact();
void display_contacts();
void search_contact();
void update_contact();
void delete_contact();

void add_contact() {
    // Write your code here

    int id;

    if (scanf("%d", &id) == 1) {
        printf("\nID: %d", id);

        if (id > 0) {
            printf("\nValid ID");

            {
                int duplicate = 0;

                for (int i = 0; i < contact_count; i++) {
                    if (phonebook[i].id == id) {
                        duplicate = 1;
                        break;
                    }
                }

                if (duplicate) {
                    printf("\nDuplicate ID");
                    return;
                }
            }

            getchar();

            if (fgets(phonebook[contact_count].name,
                      sizeof(phonebook[contact_count].name), stdin) != NULL) {
                phonebook[contact_count].name[
                    strcspn(phonebook[contact_count].name, "\n")
                ] = '\0';

                printf("\nName: %s", phonebook[contact_count].name);

                {
                    char phone_input[100];

                    if (fgets(phone_input, sizeof(phone_input), stdin) != NULL) {
                        phone_input[
                            strcspn(phone_input, "\n")
                        ] = '\0';

                        printf("\nPhone: %s", phone_input);

                        if (strlen(phone_input) >= 1 &&
                            strlen(phone_input) <= 14) {
                            strcpy(phonebook[contact_count].phone, phone_input);
                            printf("\nValid Phone");

                            phonebook[contact_count].id = id;
                            contact_count++;

                            printf("\nContact Added");
                        } else {
                            printf("\nInvalid Phone");
                        }
                    }
                }
            }
        } else {
            printf("\nInvalid ID");
        }
    }
}

void display_contacts() {
}

void search_contact() {
}

void update_contact() {
}

void delete_contact() {
}

int main() {
    int choice;

    printf("Contact Book Ready.");
    printf("\nPhonebook Capacity: %d", 100);
    printf("\nContacts: %d", contact_count);

    while (1) {
        printf("\nMenu:");

        if (scanf("%d", &choice) != 1) {
            break;
        }

        switch (choice) {
            case 1:
                printf("\nAdd");
                add_contact();
                break;

            case 2:
                printf("\nDisplay");
                display_contacts();
                break;

            case 3:
                printf("\nSearch");
                search_contact();
                break;

            case 4:
                printf("\nUpdate");
                update_contact();
                break;

            case 5:
                printf("\nDelete");
                delete_contact();
                break;

            case 0:
                printf("\nExit");
                return 0;

            default:
                printf("\nInvalid Choice");
                break;
        }
    }

    return 0;
}

Limits

Time Limit: 1s
Memory Limit: 256MB

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