在C中删除结构的成员

Question

Problem: Struct keeps the data in it after being edited.

I have a program where it manages Contacts in a struct and for some reason when I update a contact, it doesn't reset or leave the field blank if I choose not to edit it.

Update function:

void updateContact(struct Contact contact[], int update) {
    char contactInput[11] = { '\0' };
    int ans = 0;
    int contactIndex;
    int contactx;

    printf("Enter the cell number for the contact: ");
    getTenDigitPhone(contactInput);

    contactIndex = findContactIndex(contact, update, contactInput);
    contactx = findContactIndex(contact, update, contactInput);

    if (contactx == -1) {
        printf("*** Contact NOT FOUND ***\n");
    }
    else {
        printf("\nContact found:\n");
        displayContact(&contact[contactIndex]);

        printf("\nDo you want to update the name? (y or n): ");
        ans = yes();

        if (ans == 1) {
            getName(&contact[contactIndex].name);
        }

        printf("Do you want to update the address? (y or n): ");
        ans = yes();

        if (ans == 1) {
            getAddress(&contact[contactIndex].address);
        }

        printf("Do you want to update the numbers? (y or n): ");
        ans = yes();

        if (ans == 1) {
                getNumber(&contact[contactIndex].numbers);
        }      
    }    
}

Struct:

struct Contact contact[MAXCONTACTS] =
{       {           { "Rick", { '\0' }, "Grimes" },
        { 11, "Trailer Park", 0, "AJA 2J2", "King City" },
        { "4161112222", "2162223333", "4163334444" }        },

    {           { "Maggie", "R.", "Greene" },
        { 55, "Hightop House", 0, "A9A 3K3", "Bolton" },
        { "9051112222", "9052223333", "9053334444" }        },

getNumber Function:

void getNumber(struct Number *num) {
    int response;

    printf("Please enter the contact's cell phone number: ");
    getTenDigitPhone(num->cell);
    //      scanf("%10s", num->cell);
    //      *num->cell = getInt();

    printf("Do you want to enter a home phone number? (y or n): ");
    response = yes();

    if (response == 1) {
        printf("Please enter the contact's home phone number: ");
        getTenDigitPhone(num->home);
        //      scanf("%10s", num->home);
        //      *num->home = getInt();
    }

    printf("Do you want to enter a business phone number? (y or n): ");
    response = yes();

    if (response == 1) {
        printf("Please enter the contact's business phone number: ");
        getTenDigitPhone(num->business);
        //      scanf("%10s", num->business);
        //      *num->business = getInt();
    }    }

I want to leave the field blank (if I didn't update it) after I update the contact. I don't know how to delete a member struct so please help me, I will really appreciate it.

Answer 1

Set the struct field to a null pointer, or a pointer to "my blank string"
*num->cell = 0;

If you do this, you'll have to check for null later.

Or you can do *num->cell = myBlankString; , where blank string is defined as
char myBlankString[1] = ""; This is a printable, blank string.