i am getting Segmentation fault: 11
after i run the menu/ command I and i want to add the inputs to the list. Trying to figure out but i couldn't any help is appreciated
#include <stdio.h>
#include <stdlib.h>
#include <ctype.h>
#include <string.h>
#include <assert.h>
#define MAX_LENGTH 1023
//**********************************************************************
//  Linked List Definitions
//  Define your linked list node and pointer types
//  here for use throughout the file.
//
//   ADD STATEMENT(S) HERE
typedef struct contact
{
    char familyName[MAX_LENGTH+1];
    char firstName[MAX_LENGTH+1];
    char address[MAX_LENGTH+1];
    char phoneNumber[MAX_LENGTH+1];
    struct contact *link;
//pointer to next node.
} contact;
//**********************************************************************
// Linked List Function Declarations
//
// Functions that modify the linked list.
//   Declare your linked list functions here.
//
//   ADD STATEMENT(S) HERE
//**********************************************************************
// Support Function Declarations
//
//Teacher's function:
void safegets (char s[], int arraySize);        // gets without buffer overflow
void familyNameDuplicate (char familyName[]);   // marker/tester friendly
void familyNameFound (char familyName[]);       //   functions to print
void familyNameNotFound (char familyName[]);    //     messages to user
void familyNameDeleted (char familyName[]);
void phoneNumberFound (char phoneNumber[]);
void phoneNumberNotFound (char phoneNumber[]);
void printPhoneBookEmpty (void);
void printPhoneBookTitle (void);
//My funcs:
void newContact (char familyName[], char firstName[], char address[], char phoneNumber[], contact **p);//want to modify something
void contactDel (contact **p, char familyName[]);
/* remove head */
contact *contact_search (contact *c, char familyName[]);
/* By Family Name*/
contact *phone_search (contact *c, char phoneNumber[]);
void print_all (contact *head);
void DelAll (contact **p);
//**********************************************************************
// Program-wide Constants
//
const char NULL_CHAR = '\0';
const char NEWLINE = '\n';
//**********************************************************************
// Main Program
//
int main (void)
{
    contact *head=NULL;
    contact *temp=NULL;
    const char bannerString[]
        = "Personal Phone Book Maintenance Program.\n\n";
    const char commandList[]
        = "Commands are I (insert), D (delete), S (search by name),\n"
          "  R (reverse search by phone #), P (print), Q (quit).\n";
    // Declare linked list head.
    //   ADD STATEMENT(S) HERE TO DECLARE LINKED LIST HEAD.
    // announce start of program
    printf("%s",bannerString);
    printf("%s",commandList);
    char response;
    char res[MAX_LENGTH+1];
    char input[MAX_LENGTH+1];
    char familyName[MAX_LENGTH+1];
    char firstName[MAX_LENGTH+1];
    char address[MAX_LENGTH+1];
    char phoneNumber[MAX_LENGTH+1];
        //to pass char arrays to insert function
    do
    {
        printf("\nCommand?: ");
        safegets(input,MAX_LENGTH+1);
        // Response is first char entered by user.
        // Convert to uppercase to simplify later comparisons.
        response = toupper(input[0]);
        if (response == 'I')
        {
        // Insert an phone book entry into the linked list.
            // Maintain the list in alphabetical order by family name.
            //   ADD STATEMENT(S) HERE
        // USE THE FOLLOWING PRINTF STATEMENTS WHEN PROMPTING FOR DATA:
            printf("  family name: ");
        fgets(familyName, MAX_LENGTH+1, stdin);
            printf("  first name: ");
        fgets(firstName, MAX_LENGTH+1, stdin);
            printf("  address: ");
        fgets(address, MAX_LENGTH+1, stdin);
            printf("  phone number: ");
        fgets(familyName, MAX_LENGTH+1, stdin);
        newContact(familyName, firstName, address, phoneNumber, &head);
        }
        else if (response == 'D')
        {
            // Delete an phone book entry from the list.
            //   ADD STATEMENT(S) HERE
            printf("\nEnter family name for entry to delete: ");
        fgets(res,MAX_LENGTH,stdin);
        contactDel(&head, res);
        }
        else if (response == 'S')
        {
            // Search for an phone book entry by family name.
            printf("\nEnter family name to search for: ");
        fgets(familyName, MAX_LENGTH, stdin);
            temp=contact_search(head, familyName);
            if (temp == NULL)
            familyNameFound(res);
            else
        {
            printf("%s\n%s\n%s\n%s\n\n", temp->familyName, temp->firstName, temp->address, temp->phoneNumber);
        }
            //   ADD STATEMENT(S) HERE
        }
        else if (response == 'R')
        {
            // Search for an phone book entry by phone number.
            //ADD STATEMENT(S) HERE
            printf("\nEnter phone number to search for: ");
            fgets(phoneNumber,MAX_LENGTH,stdin);
            temp = phone_search(head, phoneNumber);
            if (temp==NULL)
                phoneNumberNotFound(phoneNumber);
            else
            {
                phoneNumberFound(phoneNumber);
                printf("\n%s\n%s\n%s\n%s\n", temp->familyName, temp->firstName, temp->address, temp->phoneNumber);
            }
        }
        else if (response == 'P')
        {
            // Print the phone book.
            //   ADD STATEMENT(S) HERE
            print_all(head);
        }
        else if (response == 'Q')
        {
            ;// do nothing, we'll catch this below
        }
        else
        {
            // do this if no command matched ...
            printf("\nInvalid command.\n%s\n",commandList);
        }
    } while (response != 'Q');
    // Delete the whole phone book linked list.
    //   ADD STATEMENT(S) HERE
    DelAll(&head);
    // Print the linked list to confirm deletion.
    //   ADD STATEMENT(S) HERE
    print_all (head);
    return 0;
}
//**********************************************************************
// Support Function Definitions
// Function to get a line of input without overflowing target char array.
void safegets (char s[], int arraySize)
{
    int i = 0, maxIndex = arraySize-1;
    char c;
    while (i < maxIndex && (c = getchar()) != NEWLINE)
    {
        s[i] = c;
        i++;
    }
    s[i] = NULL_CHAR;
}
// Function to call when user is trying to insert a family name
// that is already in the book.
void familyNameDuplicate (char familyName[])
{
    printf("\nAn entry for <%s> is already in the phone book!\n"
           "New entry not entered.\n",familyName);
}
// Function to call when a family name was found in the phone book.
void familyNameFound (char familyName[])
{
    printf("\nThe family name <%s> was found in the phone book.\n",
             familyName);
}
// Function to call when a family name was not found in the phone book.
void familyNameNotFound (char familyName[])
{
    printf("\nThe family name <%s> is not in the phone book.\n",
             familyName);
}
// Function to call when a family name that is to be deleted
// was found in the phone book.
void familyNameDeleted (char familyName[])
{
    printf("\nDeleting entry for family name <%s> from the phone book.\n",
             familyName);
}
// Function to call when a phone number was found in the phone book.
void phoneNumberFound (char phoneNumber[])
{
    printf("\nThe phone number <%s> was found in the phone book.\n",
             phoneNumber);
}
// Function to call when a phone number was not found in the phone book.
void phoneNumberNotFound (char phoneNumber[])
{
    printf("\nThe phone number <%s> is not in the phone book.\n",
             phoneNumber);
}
// Function to call when printing an empty phone book.
void printPhoneBookEmpty (void)
{
    printf("\nThe phone book is empty.\n");
}
// Function to call to print title when whole phone book being printed.
void printPhoneBookTitle (void)
{
    printf("\nMy Personal Phone Book: \n");
}
//**********************************************************************
// Add your functions below this line.
//   ADD STATEMENT(S) HERE
void newContact (char familyName[], char firstName[], char address[], char phoneNumber[], contact **head)
{
    contact *testPtr=NULL;
    testPtr = contact_search (*head, familyName);
    if (strcmp(testPtr->familyName, familyName)==0)
    {
        familyNameDuplicate(familyName);
        return;
    }
    else
        testPtr = *head;
    for ( ; strcmp(testPtr->familyName, familyName) < 0; testPtr = testPtr -> link)
    ;
    contact *c = (contact *)malloc (sizeof(contact));//new node
    strcpy(c->familyName, familyName);
    strcpy(c->firstName, firstName);
    strcpy(c->address, address);
    strcpy(c->phoneNumber, phoneNumber);
    if (head==NULL)
    {
        c->link = *head;
        *head=c;
    }
    else
    {
        ;
    }
}
void contactDel (contact **p, char familyName[]) /* remove head */
{
    contact *control=contact_search(*p, familyName);
    if (control != NULL)
    {
        contact *n = control;
        control = control -> link;
        free(n);
    }
}
void DelAll (contact **p)
{
    if (*p != NULL)
    {
        contact *n = *p;
        *p = (*p)->link;
        free(n);
    }
    return;
}
contact *contact_search (contact *c, char familyName[]) /* By Family Name*/
{
    while (c != NULL)
    {
        if (strcmp(c->familyName, familyName)==0)
        {
            return c;
        }
        c = c->link;
    }
    return NULL;
}
contact *phone_search (contact *c, char phoneNumber[])
{
    while (c != NULL)
    {
        if (strcmp(c->phoneNumber, phoneNumber)==0)
        {
            return c;
        }
        c = c->link;
    }
    return NULL;
}
void print_all (contact *head)
{
    if (head == NULL)
    {
        printPhoneBookEmpty();
    }
    else
    {
            printPhoneBookTitle();
        while (head != NULL)
            {
                printf("%s\n%s\n%s\n%s\n\n", head->familyName, head->firstName, head->address, head->phoneNumber);
            head = head->link;
            }
    }
}
the program should keep the inputs in the list and then print them after it gets the option from the user. and so on but why am i getting the segmentation failure?
 
    