Experiment 1.1: String Analysis, Matrix Operations, and Banking System

These are the concepts from the first lecture days that this experiment depends on. Revise each one before writing any code.

public class Demo {
    public static void main(String[] args) {
        System.out.println("Hello, Java!");
    }
}

int count = 0;
double balance = 5000.0;
String name = "Aman";
final double MIN_BALANCE = 0.0;

if (amount > 0 && amount <= balance) { ... }
double avg = (double) sum / count;

Scanner sc = new Scanner(System.in);
int id = sc.nextInt();
sc.nextLine(); // consume leftover newline
String name = sc.nextLine();

switch (choice) {
    case 1: /* deposit */  break;
    case 2: /* withdraw */ break;
    default: System.out.println("Invalid choice!");
}

int[] numbers = new int[10];       // 1D array
int[][] matrix = new int[2][3];    // 2 rows, 3 columns
matrix[0][1] = 7;                  // row 0, column 1

class BankAccount {
    private double balance;          // hidden data
    public void deposit(double amt)  { /* validated */ }
    public void withdraw(double amt) { /* validated */ }
}

public BankAccount(String name, String accNo, double bal) {
    this.accountHolderName = name;
    this.accountNumber = accNo;
    this.balance = bal;
}

Problem statement: Write a Java program to analyse a string input by the user. The program should count the number of vowels, consonants, digits, and special characters in the string.

Algorithm

1. Start the program and create a Scanner object.
2. Read the complete string using nextLine().
3. Initialise counters for vowels, consonants, digits, and special characters.
4. Loop through every character in the string.
5. If the character is a letter, check whether it is a vowel or consonant.
6. If it is not a letter, check whether it is a digit.
7. If it is neither a letter nor digit, count it as a special character.
8. Print all counts.

Java Program

import java.util.Scanner;

public class CharacterCounter {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);

        System.out.print("Enter a string: ");
        String input = scanner.nextLine();

        int vowelCount = 0;
        int consonantCount = 0;
        int digitCount = 0;
        int specialCount = 0;

        String vowels = "AEIOUaeiou";

        for (char ch : input.toCharArray()) {
            if (Character.isLetter(ch)) {
                if (vowels.indexOf(ch) != -1) {
                    vowelCount++;
                } else {
                    consonantCount++;
                }
            } else if (Character.isDigit(ch)) {
                digitCount++;
            } else {
                specialCount++;
            }
        }

        System.out.println("Vowels: " + vowelCount);
        System.out.println("Consonants: " + consonantCount);
        System.out.println("Digits: " + digitCount);
        System.out.println("Special Characters: " + specialCount);

        scanner.close();
    }
}

Sample Output

Enter a string: Hello World 123!
Vowels: 3
Consonants: 7
Digits: 3
Special Characters: 3

Problem statement: Write a Java program to perform matrix operations (addition, subtraction, and multiplication) on two matrices provided by the user. The program should check the dimensions of the matrices to ensure valid operations.

Algorithm

1. Read rows and columns for Matrix A.
2. Read all elements of Matrix A using nested loops.
3. Read rows and columns for Matrix B.
4. Read all elements of Matrix B using nested loops.
5. If dimensions are equal, perform addition and subtraction; otherwise print why they are not possible.
6. If colsA == rowsB, perform multiplication; otherwise print why it is not possible.
7. Display every result matrix row by row.

Java Program

import java.util.Scanner;

public class MatrixOperations {

    public static int[][] inputMatrix(Scanner scanner, int rows, int cols) {
        int[][] matrix = new int[rows][cols];
        System.out.println("Enter elements for matrix (" + rows + "x" + cols + "):");

        for (int i = 0; i < rows; i++) {
            for (int j = 0; j < cols; j++) {
                matrix[i][j] = scanner.nextInt();
            }
        }

        return matrix;
    }

    public static void displayMatrix(int[][] matrix) {
        for (int[] row : matrix) {
            for (int element : row) {
                System.out.print(element + " ");
            }
            System.out.println();
        }
    }

    public static int[][] addMatrices(int[][] a, int[][] b, int rows, int cols) {
        int[][] result = new int[rows][cols];

        for (int i = 0; i < rows; i++) {
            for (int j = 0; j < cols; j++) {
                result[i][j] = a[i][j] + b[i][j];
            }
        }

        return result;
    }

    public static int[][] subtractMatrices(int[][] a, int[][] b, int rows, int cols) {
        int[][] result = new int[rows][cols];

        for (int i = 0; i < rows; i++) {
            for (int j = 0; j < cols; j++) {
                result[i][j] = a[i][j] - b[i][j];
            }
        }

        return result;
    }

    public static int[][] multiplyMatrices(
            int[][] a, int[][] b, int rowsA, int colsA, int colsB) {

        int[][] result = new int[rowsA][colsB];

        for (int i = 0; i < rowsA; i++) {
            for (int j = 0; j < colsB; j++) {
                for (int k = 0; k < colsA; k++) {
                    result[i][j] += a[i][k] * b[k][j];
                }
            }
        }

        return result;
    }

    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);

        System.out.print("Enter the number of rows and columns for Matrix A: ");
        int rowsA = scanner.nextInt();
        int colsA = scanner.nextInt();
        int[][] matrixA = inputMatrix(scanner, rowsA, colsA);

        System.out.print("Enter the number of rows and columns for Matrix B: ");
        int rowsB = scanner.nextInt();
        int colsB = scanner.nextInt();
        int[][] matrixB = inputMatrix(scanner, rowsB, colsB);

        if (rowsA == rowsB && colsA == colsB) {
            System.out.println("\nMatrix Addition:");
            displayMatrix(addMatrices(matrixA, matrixB, rowsA, colsA));

            System.out.println("\nMatrix Subtraction:");
            displayMatrix(subtractMatrices(matrixA, matrixB, rowsA, colsA));
        } else {
            System.out.println("\nAddition and subtraction not possible.");
            System.out.println("Dimensions must match.");
        }

        if (colsA == rowsB) {
            System.out.println("\nMatrix Multiplication:");
            displayMatrix(multiplyMatrices(matrixA, matrixB, rowsA, colsA, colsB));
        } else {
            System.out.println("\nMultiplication not possible.");
            System.out.println("Matrix A columns must equal Matrix B rows.");
        }

        scanner.close();
    }
}

Sample Output

Enter the number of rows and columns for Matrix A: 2 2
Enter elements for matrix (2x2):
1 2
3 4
Enter the number of rows and columns for Matrix B: 2 2
Enter elements for matrix (2x2):
5 6
7 8

Matrix Addition:
6 8
10 12

Matrix Subtraction:
-4 -4
-4 -4

Matrix Multiplication:
19 22
43 50

Problem statement: Create a Java program to implement a basic banking system with the following features: account creation (Name, Account Number, Balance), deposit and withdrawal operations, and prevention of overdraft by checking the balance before withdrawal.

Algorithm

1. Read the account holder name, account number, and initial balance.
2. Create a BankAccount object using the constructor.
3. Repeat: display the menu (Deposit, Withdraw, Display Details, Exit) and read the choice.
4. For Deposit, read the amount and add it to the balance only if it is positive.
5. For Withdraw, read the amount and deduct it only if it is positive and does not exceed the balance; otherwise report insufficient balance.
6. For Display Details, print the holder name, account number, and current balance.
7. For Exit, print a closing message and stop; for any other choice, print an error and show the menu again.

Java Program

import java.util.Scanner;

class BankAccount {
    private String accountHolderName;
    private String accountNumber;
    private double balance;

    // Constructor to initialise account
    public BankAccount(String name, String accNumber, double initialBalance) {
        this.accountHolderName = name;
        this.accountNumber = accNumber;
        this.balance = initialBalance;
    }

    // Method to deposit money
    public void deposit(double amount) {
        if (amount > 0) {
            balance += amount;
            System.out.println("Rs." + amount + " deposited successfully.");
        } else {
            System.out.println("Invalid deposit amount.");
        }
    }

    // Method to withdraw money (overdraft prevented)
    public void withdraw(double amount) {
        if (amount > 0 && amount <= balance) {
            balance -= amount;
            System.out.println("Rs." + amount + " withdrawn successfully.");
        } else if (amount > balance) {
            System.out.println("Insufficient balance!");
        } else {
            System.out.println("Invalid withdrawal amount.");
        }
    }

    // Method to display account details
    public void displayAccountDetails() {
        System.out.println("\nAccount Details:");
        System.out.println("Account Holder: " + accountHolderName);
        System.out.println("Account Number: " + accountNumber);
        System.out.println("Current Balance: Rs." + balance);
    }
}

public class BankingSystem {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);

        System.out.print("Enter Account Holder Name: ");
        String name = scanner.nextLine();

        System.out.print("Enter Account Number: ");
        String accNumber = scanner.nextLine();

        System.out.print("Enter Initial Balance: Rs.");
        double initialBalance = scanner.nextDouble();

        BankAccount account = new BankAccount(name, accNumber, initialBalance);
        System.out.println("\nAccount created successfully!");

        while (true) {
            System.out.println("\n--- Banking System Menu ---");
            System.out.println("1. Deposit");
            System.out.println("2. Withdraw");
            System.out.println("3. Display Account Details");
            System.out.println("4. Exit");
            System.out.print("Enter your choice: ");
            int choice = scanner.nextInt();

            switch (choice) {
                case 1:
                    System.out.print("Enter deposit amount: Rs.");
                    double depositAmount = scanner.nextDouble();
                    account.deposit(depositAmount);
                    break;
                case 2:
                    System.out.print("Enter withdrawal amount: Rs.");
                    double withdrawAmount = scanner.nextDouble();
                    account.withdraw(withdrawAmount);
                    break;
                case 3:
                    account.displayAccountDetails();
                    break;
                case 4:
                    System.out.println("Thank you for using our banking system!");
                    scanner.close();
                    return;
                default:
                    System.out.println("Invalid choice! Please select a valid option.");
            }
        }
    }
}

Sample Output

Enter Account Holder Name: Aman Kumar
Enter Account Number: CU1234567
Enter Initial Balance: Rs.5000

Account created successfully!

--- Banking System Menu ---
1. Deposit
2. Withdraw
3. Display Account Details
4. Exit
Enter your choice: 1
Enter deposit amount: Rs.2000
Rs.2000.0 deposited successfully.

--- Banking System Menu ---
1. Deposit
2. Withdraw
3. Display Account Details
4. Exit
Enter your choice: 2
Enter withdrawal amount: Rs.10000
Insufficient balance!

--- Banking System Menu ---
1. Deposit
2. Withdraw
3. Display Account Details
4. Exit
Enter your choice: 3

Account Details:
Account Holder: Aman Kumar
Account Number: CU1234567
Current Balance: Rs.7000.0

--- Banking System Menu ---
1. Deposit
2. Withdraw
3. Display Account Details
4. Exit
Enter your choice: 4
Thank you for using our banking system!