Singly linked list // 2

gistfile1.c

/*
*http://stackoverflow.com/questions/23317646/why-is-strcpy-unsafe-in-c
We can use strncpy instead of strcpy. It's safer. 
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#define MAX_SIZE 10

typedef struct teacherData{

    int teacherId;
    char teacherName[MAX_SIZE];
    char teacherDesign[MAX_SIZE]; // Refer to Teacher Designation

    struct teacherData *next;

}teacher;

void searchNode(teacher *listNode, int value);
teacher *deleteNode(teacher *listNode, int value);
void printLinkedList(teacher *listNode);
teacher *insertNewNode(teacher *listNode, int id, char name[], char designation[]);
char getOption();
void menu(void);
int main()
{

    teacher *linkList;
    int id;
    char name[MAX_SIZE];
    char designation[MAX_SIZE];

    linkList = NULL;

    static const char extValue = '5';

    menu();
    char choice;

    do{
        switch(choice = getOption())
        {
            case '1' : printf("\n\nTeacher id: ");
                       scanf("%d",&id);
                       printf("Teacher name: ");
                       fflush(stdin);
                       gets(name);
                       printf("Teacher Designation: ");
                       gets(designation);
                       fflush(stdin);
                       linkList = insertNewNode(linkList,id,name,designation);
                       break;
            case '2' : printf("\nId number: ");
                       scanf("%d",&id);
                       linkList = deleteNode(linkList,id);
                       break;
            case '3' : printLinkedList(linkList);
                       break;
            case '4' : printf("\nID: ");
                       scanf("%d",&id);
                       searchNode(linkList,id);
                       break;
            case '5':  break;
        }

    }
    while(choice != extValue);

    return 0;
}

void searchNode(teacher *listNode, int value){

    teacher *node;
    node = listNode;
    while(node != NULL){
        if(node->teacherId == value){
            printf("\nGood news, %d. teacher found.",value);
            printLinkedList(node);
            return;
        }
        node = node->next;
    }
    printf("\nSorry, Not found %d.teacher.. \n",value);
}

teacher *deleteNode(teacher *listNode, int value){
    teacher *node, *previosNode;
    /*If node is in 1 record.*/
    node = listNode;
    if(listNode->teacherId == value){
        printf("DELETED");
        node = listNode;
        free(node);
        listNode = listNode->next;
        return listNode;
    }
    else{
            while(node != NULL && node->teacherId != value){
                previosNode = node;
                node = node->next;
            }
            if(node == NULL){
                printf("\nDeletion failed.\n");
                return NULL;
            }
            else if (node->teacherId == value){
                previosNode->next = node->next;
                free(node);
                return listNode;
            }
    }
}

void printLinkedList(teacher *listNode){
    teacher *list;
    list = listNode;
    printf("\n\n Details..\n\n");
    while(list != NULL){
        printf("\nTeacher id: %d\nTeacher name: %s\nTeacher Designation: %s\n",list->teacherId,list->teacherName,list->teacherDesign);
        list = list->next;
    }
}

teacher *insertNewNode(teacher *listNode, int id, char name[], char designation[]){

    teacher *newNode = (teacher*)malloc(sizeof(teacher));

    if(newNode == NULL){
        printf("Memory mistake, sorry..");
        exit(1);
    }

    newNode->teacherId = id;
    strcpy(newNode->teacherName,name);
    strcpy(newNode->teacherDesign,designation);
    newNode->next = listNode; /*Necessary for function which returns NULL to traverse.*/
    listNode = newNode;
    return listNode; /*This statement always returns NULL, we know listNode's parameter function's arguments.*/
}

/*Our menu which is showed by the computer*/
void menu(){
    printf("----------------------------------\n");
    printf("1 - Insert node into the list\n");
    printf("2 - Delete a node in the list\n");
    printf("3 - Display the list\n");
    printf("4 - Search the list\n");
    printf("5 - EXIT\n");
    printf("----------------------------------\n");
}

/*Returning option.*/
char getOption(){

    char opt;
    printf("\nEnter your option: ");
    switch(opt=getch()){

        case '1':
        case '2':
        case '3':
        case '4':
        case '5': return opt;
        default : printf("\nInvalid Choice.\n");
    }
        return opt; //  For example, when user entered '1'
                    //  function returns this area so returned 1.
}