1.

School management system

#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#define size 100

// Define a structure to store student and teacher information

struct student
{
int ID, Age, atten, TID, TAge, Tsalary;
char name[50], Add[50], gen[50], Tname[50], TAdd[50], Tgen[10], rank[50];
};

// Global variables for student and teacher records

struct student stud[size];
int studentcount = 0; // Counter for students
int teachercount = 0; // Counter for teachers

// Function to add a new student record

void student_rec()
{
FILE *fptr = fopen("Student_rec.txt", "w");
if (fptr == NULL)
{
printf("Error opening the file!");
}
if (studentcount < size)
{
printf("\nEnter the student ID: ");
scanf("%d", &stud[studentcount].ID);
printf("Enter the student name: ");
scanf("%s", &stud[studentcount].name);
printf("Enter the student gender: ");
scanf("%s", &stud[studentcount].gen);
printf("Enter the student Age: ");
scanf("%d", &stud[studentcount].Age);
printf("Enter the student address: ");
scanf("%s", &stud[studentcount].Add);
printf("Enter the student attendance (X out of 365):
"); scanf("%d", &stud[studentcount].atten);
printf("Record of %s with ID: %d was added successfully!\n", stud[studentcount].name,
stud[studentcount].ID);
fprintf(fptr, "ID: %d,\tName: %s\tGender: %s\tAge: %d\tAddress: %s\tAttendance: %d\n",
stud[studentcount].ID, stud[studentcount].name, stud[studentcount].gen, stud[studentcount].Age,
stud[studentcount].Add, stud[studentcount].atten);
studentcount++;
}
else
 {
printf("Maximum amount of student record has been reached. No more records can be added.");
}
fclose(fptr);
}

// Function to add a new teacher or staff record

void teacher_rec()
{
FILE *fptr = fopen("Teacher_rec.txt", "w");
if (fptr == NULL)
{
printf("Error opening the file!");
}
if (teachercount < size)
{
printf("\nEnter the teacher/staff ID: ");
scanf("%d", &stud[teachercount].TID);
printf("Enter the name: ");
scanf("%s", &stud[teachercount].Tname);
printf("Enter the rank (teacher or staff) of %s: ", stud[teachercount].Tname);
scanf("%s", &stud[teachercount].rank);
printf("Enter the gender: ");
scanf("%s", &stud[teachercount].Tgen);
printf("Enter the Age: ");
scanf("%d", &stud[teachercount].TAge);
printf("Enter the address: ");
scanf("%s", &stud[teachercount].TAdd);
printf("Enter the salary: ");
scanf("%d", &stud[teachercount].Tsalary);
printf("Record of %s with ID: %d was added successfully!\n", stud[teachercount].Tname,
stud[teachercount].TID);
fprintf(fptr, "ID: %d\t\tName: %s\t\tRank: %s\t\tGender: %s\t\tAge: %d\t\tAddress: %s\t\tSalary: %d\n",
stud[teachercount].TID, stud[teachercount].Tname, stud[teachercount].rank, stud[teachercount].Tgen,
stud[teachercount].TAge, stud[teachercount].TAdd, stud[teachercount].Tsalary);
teachercount++;
}
fclose(fptr);
}

// Function to display the total number of student records

void student_count()
{
if (studentcount == 0)
{
printf("No record of any student was found.\nTo enter the record of student please enter the respective
number 1 for it.");
}
 else
{
printf("\nOut of 100 records, you have entered the record of %d students.\n", studentcount);
int vacant = 100 - studentcount;
printf("You have space for %d more records", vacant);
}
}

// Function to display the total number of teacher or staff records

void teacher_count()
{
if (teachercount == 0)
{
printf("No record of any teacher was found.\nTo enter the record of teacher/staff please enter the respective
number 2 for it.");
}
else
{
printf("\nOut of 100 records, you have entered the record of %d teachers.\n", teachercount);
int vacant = 100 - teachercount;
printf("You have space for %d more records", vacant);
}
}

// Function to display all student records

void display_stud()
{
if (studentcount == 0)
{
printf("\nNo record of student was found");
}
else
{
printf("\nThe list of student info recorded so far is as follows:\n");

printf("*********************************************************************************
***************************\n");
for (int i = 0; i < studentcount; i++)
{
printf("SN: %d\tID: %d\tName: %s\tGender: %s\tAge: %d\tAddress: %s\tAttendance: %d\n", i + 1,
stud[i].ID, stud[i].name, stud[i].gen, stud[i].Age, stud[i].Add, stud[i].atten);
}

printf("*********************************************************************************
***************************\n");
}
}
// Function to display all teacher or staff records
void display_teach()
{
if (teachercount == 0)
{
printf("\nNo record of teacher/staff was found");
}
else
{
printf("\nThe list of teacher/staff info recorded so far is as follows:\n");

printf("*********************************************************************************
***************************\n");
for (int i = 0; i < teachercount; i++)
{
printf("SN: %d\tID: %d\tName: %s\tRank: %s\tGender: %s\tAge: %d\tAddress: %s\tSalary: %d\n", i + 1,
stud[i].TID, stud[i].Tname, stud[i].rank, stud[i].Tgen, stud[i].TAge, stud[i].TAdd, stud[i].Tsalary);
}

printf("*********************************************************************************
***************************\n");
}
}

// Function to find and display student information by ID

void find_student_by_ID()
{
int searchID, found = 0;
printf("Enter the ID of the student: ");
scanf("%d", &searchID);
for (int i = 0; i < studentcount; i++)
{
if (stud[i].ID == searchID)
{
printf("\nStudent ID: %d\n", stud[i].ID);
printf("Student Name: %s\n", stud[i].name);
printf("Student Gender: %s\n", stud[i].gen);
printf("Student Age: %d\n", stud[i].Age);
printf("Student Address: %s\n", stud[i].Add);
printf("Student Attendance: %d\n", stud[i].atten);
found = 1;
}
}
if (!found)
{
printf("\nThere was no record of a student with ID: %d", searchID);
}
}
// Function to find and display teacher information by ID
void find_teacher_by_ID()
{
int searchID, found = 0;
printf("Enter the ID: ");
scanf("%d",
&searchID);
for (int i = 0; i < teachercount; i++)
{
if (stud[i].TID == searchID)
{
printf("\nID: %d\n", stud[i].TID);
printf("Name: %s\n", stud[i].Tname);
printf("Rank: %s\n", stud[i].rank);
printf("Gender: %s\n", stud[i].Tgen);
printf("Age: %d\n", stud[i].TAge);
printf("Student Address: %s\n", stud[i].TAdd);
printf("Salary %d\n", stud[i].Tsalary);
found = 1;
break;
}
}
if (!found)
{
printf("\nNo records were found with ID: %d", searchID);
}
}

// Main function to handle user interaction

int main()
{
int choice;
char c;
printf("--------------------------------------WELCOME TO THE ABC SCHOOL MANAGEMENT SYSTEM-------
");
top:
printf("\n\nPlease select what you want to do: ");
printf("\n\na) For adding new student record, press:
1\n"); printf("b) For adding
new staff or teacher record, press: 2\n");
printf("c) To display all students, press: 3\n");
printf("d) To display all teachers, press: 4\n");
printf("e) To find the student by ID, press: 5\n");
printf("f) To find the teacher/staff by ID, press: 6\n");
printf("g) To show the student count, press: 7\n");
printf("h) To show the teacher/staff count, press: 8\n");
printf("i) To exit, press: 9\n\n");
printf("Enter your choice: ");
scanf("%d", &choice);
switch (choice)
{
case 1:
{
student_rec();
break;
}
case 2:
{
teacher_rec();
break;
}
case 3:
{
display_stud();
break;
}
case 4:
{
display_teach();
break;
}
case 5:
{
find_student_by_ID();
break;
}
case 6:
{
find_teacher_by_ID();
break;
}
case 7:
{
student_count();
break;
}
case 8:
{
teacher_count();
break;
}
}

printf("\n\nDo you wish to continue? (press Y to continue, N to exit): ");

scanf("%s", &c);
if (c == 'y' || c == 'Y')
{
 goto top;
}
else
{
printf("Exiting the program.\nExit Successful!");
}
return 0;
}
Output:
Flow chart
Block diagram
2. Library Management system
#include <stdio.h>
#include <string.h>
#define storage 100

// Global variables for storing books and user information

int total_books = 5;
char books[5][100] = {"Atomic Habits", "Psychology of Money", "Ikigai", "Deep Work", "The Art of Laziness"};
char authors[5][100] = {"James Clear", "Morgan Housel", "Hector Garcia", "Cal Newport", "Kyrie Petrakis"};

// Structure to store registered user information

struct {
char username[20];
int password;
} registered_users[storage];

int registered_count = 0;

// Function to save books to a file

void save_books_to_file() {
FILE *fptr = fopen("books.txt", "w");
if (fptr == NULL) { // Check if file opens successfully
printf("Error opening the file!\n");
return;
}

// Write all books and their authors to the file

for (int i = 0; i < total_books; i++) {
 fprintf(fptr, "No. %d\nName: %s\nAuthor: %s\n\n", i + 1, books[i], authors[i]);
}

fclose(fptr); // Close the file

}

// Function to save user data and borrowed book details to a file

void save_user_data_to_file(const char *username, int password, const char *borrowed_book, const char
*borrowed_author) {
FILE *fptr = fopen("users.txt", "w");
if (fptr == NULL) { // Check if file opens successfully
printf("Error opening the file!\n");
return;
}

// Write user details and borrowed book details to the file

fprintf(fptr, "Username: %s\nPassword: %d\nBorrowed Book: %s\nAuthor: %s\n\n", username, password,
borrowed_book, borrowed_author);

fclose(fptr); // Close the file

}

// Function to search for books by their name

void search_books_by_name() {
char search_name[100];
int found = 0; // Flag to check if the book is found

printf("Enter the book name to search: ");

getchar(); // Clear the input buffer
scanf("%[^\n]%*c", search_name);

printf("\nSearch results for book name '%s':\n", search_name);

// Loop through all books to find matches

for (int i = 0; i < total_books; i++) {
if (strcmp(books[i], search_name) == 0) {
printf("Book No. %d\nName: %s\nAuthor: %s\n\n", i + 1, books[i], authors[i]);
found = 1; // Mark as found
}
}

// Print message if no books are found

if (!found) {
printf("No books found with the name '%s'.\n", search_name);
}
}

// Function to search for books by their author

void search_books_by_author() {
char search_author[100];
int found = 0; // Flag to check if the author is found

printf("Enter the author name to search: ");

getchar(); // Clear the input buffer
scanf("%[^\n]%*c", search_author);

printf("\nSearch results for author '%s':\n", search_author);

// Loop through all authors to find matches

for (int i = 0; i < total_books; i++) {
if (strcmp(authors[i], search_author) == 0) {
printf("Book No. %d\nName: %s\nAuthor: %s\n\n", i + 1, books[i], authors[i]);
found = 1; // Mark as found
}
}

// Print message if no authors are found

if (!found) {
printf("No books found by the author '%s'.\n", search_author);
}
}

// Function to validate user login credentials

int login_user(char user[], int pass) {
for (int i = 0; i < registered_count; i++) {
if (strcmp(registered_users[i].username, user) == 0 && registered_users[i].password == pass) {
return 1; // Login successful
}
}
return 0; // Login failed
}

int main() {
char user[20]; // Stores username
int pass, choice, choice2, choice3; // Variables for user choices
top:

// Main menu
printf("-------------------------------------------WELCOME TO ABC LIBRARY MANAGEMENT--------------------
\n");
printf(" Here you can add, search and borrow the needed books!\n");
printf(" Please select what you want to do:\n\n");
printf("->Sign up to our ABC library to gain access, press: 1\n");
printf(" \n Already have an account? \n\n->Login to check your books, press: 2\n");
printf("\nEnter your choice: ");
scanf("%d", &choice);
if (choice == 1) {
// Sign-up process
printf(" Enter the following information
----\n\n");
printf("Enter your username: ");
scanf("%s", user);
printf("\nEnter your password (only numbers): ");
scanf("%d", &pass);

// Save the new user details

strcpy(registered_users[registered_count].username, user);
registered_users[registered_count].password = pass;
registered_count++;

printf("\n Saving your information

- \n\n");
printf("Dear %s, This is our current list of books that we have:\n\n", user);

// Display the list of books

for (int i = 0; i < total_books; i++) {
printf("\nBook No. %d\nName: %s\nAuthor: %s\n", i + 1, books[i], authors[i]);
}

top2:
// Options after signing up or logging in
printf("\n
\n");
printf("\nTo add new books, press: 10\n");
printf("To borrow a book, press: 11\n");
printf("To search for a book by name, press: 12\n");
printf("To search for a book by author, press: 13\n");
printf("To exit, press: 14\n");
printf("To return a book, press: 15\n");
printf("\nWhat would you like to do? ");
printf("\nEnter the choice: ");
scanf("%d", &choice2);

if (choice2 == 10) {
// Adding a new book
if (total_books < 100) {
char new_book[100], new_author[100];
printf("\n Enter the following information
\n\n");
printf("Enter the name of the new book: ");
getchar(); // Clear the input buffer
scanf("%[^\n]%*c", new_book);
printf("Enter the author of the new book: ");
 scanf("%[^\n]%*c", new_author);

// Add the new book and author to the library

strcpy(books[total_books], new_book);
strcpy(authors[total_books], new_author);
total_books++;

printf("The book '%s' by %s has been added to the collection!\n", new_book, new_author);

save_books_to_file(); // Save the updated list of books to the file

printf("\nHere is the updated list of books in our library:\n");

for (int i = 0; i < total_books; i++) {
printf("\nNo. %d\nName: %s\nAuthor: %s\n", i + 1, books[i], authors[i]);
}
} else {
printf("Our inventory is currently full. Please try again later\n");
}
printf("\nTo go back, press: 1\n");
printf("To logout and go to main menu, press: 2\n");
printf("To exit the program, press: 3\n");
scanf("%d", &choice3);
printf("Enter your choice: ");
if (choice3 == 1) {
goto top2;
} else if (choice3 == 2) {
goto top;
} else {
printf("\nExiting the program. Goodbye!");
}
} else if (choice2 == 11) {
// Borrowing a book
int book_number;
printf("\nEnter the number of the book you want to borrow: ");
scanf("%d", &book_number);

if (book_number > 0 && book_number <= total_books) {

printf("\nYou have borrowed the book:\n\nBook No:%d \n%s by \n%s\n", book_number,
books[book_number - 1], authors[book_number - 1]);
save_user_data_to_file(user, pass, books[book_number - 1], authors[book_number - 1]); // Save user and
book data to the file
} else {
printf("Invalid book number. Please try again.\n");
}
printf("\nTo go back, press: 1\n");
printf("To logout and go to main menu, press: 2\n");
printf("To exit the program, press: 3\n");
scanf("%d", &choice3);
 printf("Enter your choice: ");
if (choice3 == 1) {
goto top2;
} else if (choice3 == 2) {
goto top;
} else {
printf("\nExiting the program. Goodbye!");
}
}

if (choice2 == 12) {
// Search for a book by name
search_books_by_name();
printf("\nTo go back, press: 1\n");
printf("To logout and go to main menu, press: 2\n");
printf("To exit the program, press: 3\n");
scanf("%d", &choice3);
printf("Enter your choice: ");
if (choice3 == 1) {
goto top2;
} else if (choice3 == 2) {
goto top;
} else {
printf("\nExiting the program. Goodbye!");
}
} else if (choice2 == 13) {
// Search for a book by author
search_books_by_author();
printf("\nTo go back, press: 1\n");
printf("To logout and go to main menu, press: 2\n");
printf("To exit the program, press: 3\n");
scanf("%d", &choice3);
printf("Enter your choice: ");
if (choice3 == 1) {
goto top2;
} else if (choice3 == 2) {
goto top;
} else {
printf("\nExiting the program. Goodbye!");
}
} else if (choice2 == 14) {
// Exit the library system
printf("Exiting the library system. Have a great day!\n");
}
else if (choice2 == 15) {
// Return a borrowed book
int book_number;
printf("\nEnter the number of the book you want to return: ");
 scanf("%d", &book_number);

if (book_number > 0 && book_number <= total_books) {

printf("\nYou have returned the book:\n\nBook No:%d \n%s by \n%s\n", book_number,
books[book_number - 1], authors[book_number - 1]);
save_user_data_to_file(user, pass, books[book_number - 1], authors[book_number - 1]); // Save user and
book data to the file
} else {
printf("Invalid book number. Please try again.\n");
}
printf("\nTo go back, press: 1\n");
printf("To logout and go to main menu, press: 2\n");
printf("To exit the program, press: 3\n");
scanf("%d", &choice3);
printf("Enter your choice: ");
if (choice3 == 1) {
goto top2;
} else if (choice3 == 2) {
goto top;
} else {
printf("\nExiting the program. Goodbye!");
}
}

else if (choice == 2) {
// Login process
printf("\n Enter the following information
\n\n");
printf("Enter your username: ");
scanf("%s", user);
printf("Enter your password: ");
scanf("%d", &pass);
if (login_user(user, pass)) {
printf("Login successful! Welcome, %s.\n", user);
goto top2;
}

else {
printf("Login failed. Username or password incorrect.\n");
}
}

return 0;
}
Output:
Flow Chart

Block diagram
3. Bus reservation system
#include <stdio.h>
#include <string.h>
#define MAX_USERS 100
#define MAX_BUSES 5

// Structure to store user details

struct {
char username[20];
int password;
} registered_users[MAX_USERS];

int registered_count = 0; // Counter for registered users

// Structure to store bus details

typedef struct {
char route[100];
char number_plate[10];
int price;
char status[20];
int tickets_available;
} Bus;

// List of predefined buses

Bus buses[MAX_BUSES] = {
{"Kathmandu to Pokhara", "9082", 2000, "Comfortable", 40},
{"Kathmandu to Chitwan", "7856", 2500, "Comfortable", 30},
{"Kathmandu to Surkhet", "8345", 3000, "Comparisalbe", 35},
{"Kathmandu to Jhapa", "5498", 4500, "Comfortable", 20},
{"Kathmandu to Sarlahi", "2968", 5000, "Not Comfortable", 50}
};

// Function to save user activity to a file

void save_user_data_to_file(const char *username, int password, const char *action, const char *bus_details) {
FILE *fptr = fopen("users.txt", "w");
if (fptr == NULL) {
printf("Error opening the file!\n");
return;
}
fprintf(fptr, "Username: %s\nPassword: %d\nAction: %s\nBus: %s\n\n", username, password, action,
bus_details);
fclose(fptr);
}

// Function to display all available buses

void display_buses() {
printf("\nAvailable\n");
 for (int i = 0; i < MAX_BUSES; i++) {
printf("Bus No: %d\nRoute: %s\nNumber Plate: %s\nPrice: Rs %d\nStatus: %s\nTickets Available: %d\n\n",
i + 1, buses[i].route, buses[i].number_plate, buses[i].price, buses[i].status, buses[i].tickets_available);
}
}

// Function to book tickets for a bus

void book_ticket(char username[], int password) {
int bus_number, tickets;
display_buses();
printf("Enter the bus number you want to book tickets for: ");
scanf("%d", &bus_number);

if (bus_number < 1 || bus_number > MAX_BUSES) {

printf("Invalid bus number. Please try again.\n");
return;
}

printf("Enter the number of tickets you want to book: ");

scanf("%d", &tickets);

if (tickets > buses[bus_number - 1].tickets_available) {

printf("Not enough tickets available. Please try again.\n");
return;
}

buses[bus_number - 1].tickets_available -= tickets;

printf("You have successfully booked %d tickets for the bus: %s\n", tickets, buses[bus_number - 1].route);

// Save booking information to file

save_user_data_to_file(username, password, "Booked Tickets", buses[bus_number - 1].route);
}

// Function to cancel booked tickets

void cancel_ticket(char username[], int password) {
int bus_number, tickets;
printf("Enter the bus number for which you want to cancel tickets: ");
scanf("%d", &bus_number);

if (bus_number < 1 || bus_number > MAX_BUSES) {

printf("Invalid bus number. Please try again.\n");
return;
}

printf("Enter the number of tickets you want to cancel: ");

scanf("%d", &tickets);

buses[bus_number - 1].tickets_available += tickets;

 printf("You have successfully canceled %d tickets for the bus: %s\n", tickets, buses[bus_number - 1].route);

// Save cancellation information to file

save_user_data_to_file(username, password, "Cancelled Tickets", buses[bus_number - 1].route);
}

// Function to display bus status

void check_bus_status() {
display_buses();
}

// Function to verify login credentials

int login_user(char user[], int pass) {
for (int i = 0; i < registered_count; i++) {
if (strcmp(registered_users[i].username, user) == 0 && registered_users[i].password == pass) {
return 1; // Login successful
}
}
return 0; // Login failed
}

// Main function to handle program logic

int main() {
char user[20];
int pass, choice, choice2, choice3;
top3:
// Welcome screen and main menu
printf("-----------------------------------------WELCOME TO ABC BUS RESERVATION SYSTEM------------------
\n");
printf(" Book tickets, check bus status, and more!\n");
printf(" Please select what you want to do:\n\n");
printf("->Register to our ABC bus reservation system, press: 1\n");
printf(" \n Already registered? \n\n->Login to check or bus tickets, press: 2\n");
printf("\nEnter your choice: ");
scanf("%d", &choice);

if (choice == 1) { // User registration

printf(" Enter the following information
----\n\n");
printf("Enter your username: ");
scanf("%s", user);
printf("Enter your password (only numbers): ");
scanf("%d", &pass);

strcpy(registered_users[registered_count].username, user);
registered_users[registered_count].password = pass;
registered_count++;
 printf("Registration successful! You can now log in.\n");
goto top;
} else if (choice == 2) { // User login
top:
printf(" Login
\n\n");
printf("Enter your username: ");
scanf("%s", user);
printf("Enter your password: ");
scanf("%d", &pass);

if (login_user(user, pass)) { // If login is successful

printf("Login successful! Welcome, %s.\n", user);
top2:
// Menu after successful login
printf("\nTo view available buses, press: 10\n");
printf("To book tickets, press: 11\n");
printf("To cancel tickets, press: 12\n");
printf("To check bus status, press: 13\n");
printf("To logout, press: 14\n");
printf("To exit the system, press: 15\n");
printf("\nEnter your choice: ");
scanf("%d", &choice2);

if (choice2 == 10) { // Display available buses

display_buses();
goto top2;
} else if (choice2 == 11) { // Book tickets
book_ticket(user, pass);
goto top2;
} else if (choice2 == 12) { // Cancel tickets
cancel_ticket(user, pass);
goto top2;
} else if (choice2 == 13) { // Check bus status
check_bus_status();
goto top2;
} else if (choice2 == 14) { // Logout
goto top3;
} else if (choice2 == 15) { // Exit the system
printf("Exiting the system. Goodbye!\n");
}
} else { // If login fails
printf("Login failed. Username or password incorrect.\n");
goto top;
}
}

return 0;
}
Output:
Flow Chart
Block diagram
4. Tic Tac Toe
#include <stdio.h>
#define SIZE 3 // Constant for the size of the board
char board[SIZE][SIZE]; // Tic Tac Toe board
char player = 'X'; // Starting player

// Function to initialize the board

void initializeBoard() {
for (int i = 0; i < SIZE; i++) {
for (int j = 0; j < SIZE; j++) {
board[i][j] = ' ';
}
}
}

// Function to print the board

void printBoard() {
printf("\n");
for (int i = 0; i < SIZE; i++) {
printf(" %c | %c | %c \n", board[i][0], board[i][1], board[i][2]);
if (i < SIZE - 1) {
printf("---|---|---\n");
}
}
printf("\n");
}

// Function to check for a win

int checkWin() {
for (int i = 0; i < SIZE; i++) {
// Check rows and columns
if ((board[i][0] == player && board[i][1] == player && board[i][2] == player) ||
(board[0][i] == player && board[1][i] == player && board[2][i] == player)) {
return 1; // Win found
}
}
// Check diagonals
if ((board[0][0] == player && board[1][1] == player && board[2][2] == player) ||
(board[0][2] == player && board[1][1] == player && board[2][0] == player)) {
return 1; // Win found
}
return 0; // No win
}

// Function to check for a draw

int isDraw() {
// Use only one loop to check for an empty space
for (int i = 0; i < SIZE * SIZE; i++) {
if (board[i / SIZE][i % SIZE] == ' ') {
return 0; // There is still an empty space
}
 }
return 1; // No empty spaces left
}

// Function to switch players

void switchPlayer() {
player = (player == 'X') ? 'O' : 'X';
}

// Function to make a move

void makeMove() {
int row, col;
while (1) {
printf("Player %c, enter your move (row and column: 1-3): ", player);
if (scanf("%d %d", &row, &col) != 2 || row < 1 || row > 3 || col < 1 || col > 3) {
printf("Invalid input. Please enter two numbers between 1 and 3.\n");
while(getchar() != '\n'); // Clear invalid input
continue;
}
row--; // Convert to 0-based index
col--;
if (board[row][col] == ' ') {
board[row][col] = player; // Make move
break;
} else {
printf("Invalid move. Try again.\n");
}
}
}

// Main function of the game

int main() {
initializeBoard();
while (1) {
printBoard();
makeMove();
if (checkWin()) {
printBoard();
printf("Player %c wins!\n", player);
break; // Exit on win
}
if (isDraw()) {
printBoard();
printf("It's a draw!\n");
break; // Exit on draw
}
switchPlayer();
}
return 0;
}
Output:
Flow Chart
Block Diagram
5. Telecom Billing System
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#define size 100 // Maximum number of customers that can be stored
struct customer
{
int ID; //Customer ID
char name[50]; //Customer name
float payment; // Payment made by the customer
};
struct customer cust[size]; // Array to store customer records
int customercount = 0; // Keeps track of the current number of customers

// Function to add a new customer record

void customer_rec()
{
FILE *fptr = fopen("customer_rec.txt","w");
if(fptr==NULL)
{
printf("Error opening the file!");
}
if(customercount<size)
{
printf("\nEnter the customer ID: ");
scanf("%d",&cust[customercount].ID);
printf("Enter the customer name: ");
scanf("%s",&cust[customercount].name);
printf("Enter the payment amount: ");
scanf("%f",&cust[customercount].payment);
printf("Record of %s with ID: %d was added
successfully!\n",cust[customercount].name,cust[customercount].ID);
fprintf(fptr,"ID: %d,\tName:
%f\tPayment:\n",cust[customercount].ID,cust[customercount].name,cust[customercount].payment);
customercount++;
}
else
{
printf("Maximum amount of customer record has reached. No more records can be added");
}
fclose(fptr);
}
void customer_count()
{
if(customercount==0)
{
 printf("No record of any customer was fount.\nTo enter the record of customer please enter the respective
number 1 for it.");
}
else
{
printf("\nOut of 100 record you have entered the record of %d customers.\n",customercount);
int vaccant = 100-customercount;
printf("You have space for %d more records",vaccant);
}
}

void viewRecords() {
if (customercount == 0) { // Check if there are no records to display
printf("No records found.\n");
return;
}

printf("\nCustomer Records:\n");
printf("ID\tName\t\tPayment\n");
printf(" \n");
for (int i = 0; i < customercount; i++) {
printf("%d\t%-15s\t%f\n",cust[i].ID, cust[i].name, cust[i].payment);
}
}

void modifyRecord() {
int ID;
printf("Enter customer ID to modify: ");
scanf("%d", &ID);
int found = 0;

// Search for the customer by ID

for (int i = 0; i < customercount; i++) {
if (cust[i].ID == ID) {
// Prompt user to modify the details
printf("Enter new name (current: %s): ", cust[i].name);
scanf("%49s", cust[i].name);
printf("Enter new payment amount (current: %f): ", cust[i].payment);
scanf("%f", &cust[i].payment);
printf("Record modified successfully.\n");
found = 1;
break;
}
}
if (!found) {
printf("Invalid ID.\n"); // If no record is found for the entered ID
}
}
// Function to view the payment details of a customer
void viewPayment() {
int ID;
printf("Enter customer ID to view payment: ");
scanf("%d", &ID);

// Search for the customer and display the payment details

for (int i = 0; i < customercount; i++) {
if (cust[i].ID == ID) {
printf("Payment for %s (ID: %d) is %f\n", cust[i].name, ID, cust[i].payment);
return;
}
}
printf("Invalid ID.\n"); // If the ID is not found
}

// Function to search a record by customer name

void searchRecord() {
char name[50];
printf("Enter customer name to search: ");
scanf("%49s", name);
int found = 0;

// Search for the customer by name

for (int i = 0; i < customercount; i++) {
if (strcmp(cust[i].name, name) == 0) {
printf("Record found: ID: %d, Name: %s, Payment: %f\n", cust[i].ID, cust[i].name, cust[i].payment);
found = 1;
break;
}
}
if (!found) {
printf("No record found for the name: %s\n", name); // If no customer matches the name
}
}

// Function to delete a customer record by ID

void deleteRecord() {
int ID;
printf("Enter customer ID to delete: ");
scanf("%d", &ID);
int found = 0;

// Search for the customer by ID and delete the record

for (int i = 0; i < customercount; i++) {
if (cust[i].ID == ID) {
// Shift the remaining records left to remove the entry
 for (int j = i; j < customercount - 1; j++) {
cust[j] = cust[j + 1];
}
customercount--; // Decrease the customer count
printf("Record deleted successfully.\n");
found = 1;
break;
}
}
if (!found) {
printf("Invalid ID.\n"); // If the ID is not found
}
}

int main()
{
int choice;
char c;
printf("--------------------------------------WELCOME TO THE CBA TELECOM BILLING SYSTEM----------
");
top:
printf("\n\nPlease Select what you want to do: \n");
printf("a)For adding new customer record press: 1\n");
printf("b)To view List of records press: 2\n");
printf("c)To Modify Record press: 3\n");
printf("d)To View Payment press: 4\n");
printf("e)To Search Records press: 5\n");
printf("f)To Delete Record press: 6\n");
printf("g)To Exit press: 7\n");
printf("Enter your choice: ");
scanf("%d",&choice);
switch(choice)
{
case 1:

customer_rec();
break;

case 2:

viewRecords();
break;

case 3:

modifyRecord();
break;
 case 4:

viewPayment();
break;

case 5:

searchRecord();
break;

case 6:

deleteRecord();
break;

}
printf("\n\nDo you wish continue?(press Y to continue N to exit): ");
scanf("%s",&c);
if(c=='y'||c=='Y')
{
goto top;
}
else
{
printf("Exiting the program.\nExit Successful!");
}

return 0;
}
OUTPUT:
Flow Chart
Block Diagram