⚠️ Exception Handling in C++

🎯 Aim

To study and implement exception handling in C++, using try, catch, and throw to manage runtime errors gracefully.

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📚 Theory

• Exception: An unexpected event or error that occurs during program execution (e.g., division by zero, invalid input, file not found).
• Exception Handling: A mechanism in C++ to detect and manage runtime errors without abruptly terminating the program.

🔑 Key Concepts

• try block → Contains code that may throw an exception.
• throw statement → Used to signal (raise) an exception.
• catch block → Handles the exception thrown by throw.

⚙️ Flow of Exception Handling

1. Code inside the try block is executed.
2. If an error occurs, the throw statement raises an exception.
3. The program looks for a matching catch block.
4. If found, the exception is handled; otherwise, the program terminates.

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📋 Algorithms

🧾 Division by Zero

1. Start
2. Input two numbers: numerator and denominator.
3. Place the division operation inside a try block.
4. If denominator = 0 → throw an exception.
5. If denominator ≠ 0 → perform division and display result.
6. In the catch block:
   • Display error message “Division by zero not allowed.”
7. End

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🧾 Age Validation

1. Start
2. Input age from the user.
3. Place validation inside a try block.
4. If age < 0 → throw age.
5. Else if age < 18 → throw age.
6. Else → display “Accepted”.
7. In the catch block:
   • If age < 0 → display “Invalid age”.
   • Else → display “You are below 18”.
8. End

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🧾 ATM Transaction System

1. Start
2. Initialize ATM with a default balance.
3. Display menu:
   • 1. Check Balance
   • 2. Deposit Money
   • 3. Withdraw Money
   • 4. Exit
4. Input user choice.
5. Place operations inside a try block:
   • Case 1: Display balance.
   • Case 2: Input deposit amount.
     • If amount ≤ 0 → throw exception.
     • Else add to balance.
   • Case 3: Input withdrawal amount.
     • If amount ≤ 0 → throw exception.
     • If amount > balance → throw exception.
     • Else deduct from balance.
   • Case 4: Exit program.
   • Default: Display “Invalid choice”.
6. In the catch block:
   • Display the error message received.
7. Repeat until user chooses Exit.
8. End

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🚀 Applications of Exception Handling

• Prevents abrupt program termination.
• Separates error‑handling logic from normal code.
• Improves program reliability and robustness.
• Used in:
  • File I/O operations.
  • Database connections.
  • Network programming.
  • Input validation.
  • Banking/ATM systems.

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🧠 Conclusion

• Exception handling in C++ provides a structured way to manage runtime errors.
• The keywords try, throw, and catch are used to detect and handle exceptions.
• It ensures that programs can continue execution gracefully even when unexpected errors occur.
• Exception handling is essential for building robust, user‑friendly applications.