Clinic Management System

/********************************************
 *         Clinic Management System         *
 *          Author: Mahmoud Hashem          *
 *              Version: v0.1               *
 ********************************************/

/* Headers */
#include <stdio.h>
#include <stdlib.h>

/* Defining Data types used */
typedef unsigned char u8;       // 1 byte  unsigned char     variable %c
typedef signed char s8;         // 1 byte  signed   char     variable %c

typedef unsigned short u16;     // 2 bytes unsigned integer  variable %hu
typedef signed short s16;       // 2 bytes signed   integer  variable %hd

typedef unsigned long u32;      // 4 bytes unsigned integer  variable %lu
typedef signed long s32;        // 4 bytes signed   integer  variable %ld

typedef unsigned long long u64; // 8 bytes unsigned integer  variable %llu
typedef signed long long s64;   // 8 bytes signed   integer  variable %lld

typedef float f32;              // 4 bytes signed   floating variable %f
typedef double f64;             // 8 bytes signed   floating variable %lf

#define STRING_MAX_LENGTH 127

void modeSelect(void);  // Mode select function         DONE
void checkAdmin(void);  // Check admin mode password    DONE
void userMode(void);    // User mode function           TODO
void adminMode(void);   // Admin mode function          TODO
void getData(void);     // Get patient data             TODO
void addPatient(void);  // Function too add patients    TODO
void checkID(u8 ID);    // Check if ID exists           TODO
void editPatient(void); // Edit patient record          TODO
void manageSlot(void);  // Reserve or cancel a slot     TODO
u8 scanChoice(void);    // Scanf admin choice           DONE

void writeToFile(u16 id, s8 *name, u8 age, s8 *gender);

typedef struct patient patient; // Declaring structure of patient

struct patient {
    u16 id;
    s8 name[STRING_MAX_LENGTH];
    u16 age;
    s8 gender[STRING_MAX_LENGTH];
    patient *link;
};

patient *head;

/* Main */
int main() {
    printf("*****************************************\n"
           "*\t\tWELCOME TO\t\t*\n"
           "*\tClinic Management System v1.0\t*\n"
           "*****************************************\n");
    modeSelect();

    return 0;
}
void modeSelect() {
    printf("*\tFor admin mode, Enter 1\t\t*\n"
           "*\tFor user mode, Enter 2\t\t*\n"
           "*\tTo exit, Enter 3\t\t*\n"
           "*****************************************\n");

    u8 mode;
    printf("Your choice:");
    scanf("%c", &mode);
    if (mode == '1') adminMode();
    /*else if (mode == '2');
    else if (mode == '3') exit(0);
    else {
        printf("Please use the options given, Try again...");
        modeSelect();
    }*/
}

void checkAdmin() {
    u8 i = '2';
    u16 pass;
    printf("\nPlease enter the password to enter admin mode\nPassword:");
    while (1) {
        scanf("%hu", &pass);
        if (pass == 1234) return;
        else if (i == '0') {
            printf("You have no remaining trails! Exiting the program...");
            exit(0);
        } else
            printf("Incorrect password!\nYou have remaining %c trails\nEnter the password:", i);
        i--;
    }
}

void adminMode() {
    printf("+-----------------------------------------------+\n"
           "|\tWelcome To Admin Mode\t\t\t|\n"
           "|\tYou here can edit, add patient\t\t|\n"
           "|\trecords, reserve and cancel slots\t|\n"
           "|\tPlease enter the password.\t\t|\n"
           "+-----------------------------------------------+\n"
    );
    checkAdmin();
    printf("+-------------------------------------------------------+\n"
           "|\tTo add a new patient, Enter 1\t\t\t+\n"
           "|\tTo edit a patient record, Enter 2\t\t+\n"
           "|\tTo reserve a slot with the doctor, or\t\t+\n"
           "|\tto cancel a reservation, Enter 3\t\t+\n"
           "+-------------------------------------------------------+\n"
    );
    u8 choice = '1';
    printf("Your choice: ");
    scanf(" %c", &choice);
    if (choice == '1') addPatient();
    /*else if (choice == 2) editPatient();
    else if (choice == 3) manageSlot();*/
}

u16 NUMBER_OF_PATIENTS = 0;
u8 FIRST_NODE = 0;

void addPatient() {
    patient *ptr, *temp;
    ptr = head;
    printf("Enter patient data\n");
    temp = (patient*) malloc(sizeof(patient));
    if (FIRST_NODE == 0) {
        printf("aaEnter patient ID: ");
        scanf(" %hu", &temp->id);
        printf("\nEnter patient name: ");
        scanf(" %[^\n]s", temp->name);
        printf("\nEnter patient age: ");
        scanf(" %hu", &temp->age);
        printf("\nEnter patient gender: ");
        scanf(" %s", temp->gender);
        temp->link = NULL;
        writeToFile(temp->id, temp->name, temp->age, temp->gender);
        head = temp;
        FIRST_NODE = 1;
    }

    else {
        printf("ssEnter patient ID: ");
        scanf(" %hu", &temp->id);
        printf("Enter patient name: ");
        scanf(" %[^\n]s", temp->name);
        printf("Enter patient age: ");
        scanf(" %hu", &temp->age);
        printf("Enter patient gender: ");
        scanf(" %s", temp->gender);
        writeToFile(temp->id, temp->name, temp->age, temp->gender);
        temp->link = NULL;
        while (ptr->link != NULL) {
            ptr = ptr -> link;
        }
        ptr -> link = temp;
    }
}

void writeToFile(u16 id, s8 *name, u8 age, s8 *gender) {
    FILE *fp = fopen("patients.txt", "w");
    fprintf(fp, "%hu\t%s\t%hu\t%s\n", id, name, age, gender);
}