Throwing exceptions in C++ - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to throw an exception with the message "Error occurred".

C++

throw [1];

Drag options to blanks, or click blank then click option'

A"Error occurred"

Bthrow

Cstd::exception

DError occurred

Attempts:

3 left

💡 Hint

Common Mistakes

Forgetting the quotes around the error message.

Trying to throw the keyword 'throw' itself.

Throwing an undefined variable.

The throw keyword is followed by the exception object or value to throw. Here, a string literal "Error occurred" is thrown as an exception.

2fill in blank

medium

Complete the code to throw a standard exception object.

C++

throw [1]();

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Astd::exception

Bexception

Clogic_error

Druntime_error

Attempts:

3 left

💡 Hint

Common Mistakes

Omitting the std:: namespace prefix.

Using a class that does not exist or is misspelled.

Throwing the class name without parentheses.

The standard exception class in C++ is std::exception. Throwing std::exception() creates and throws a default exception object.

3fill in blank

hard

Fix the error in the code to correctly throw an integer exception.

C++

throw [1];

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A"5"

Bint

C5

Dthrow

Attempts:

3 left

💡 Hint

Common Mistakes

Using quotes around the number, making it a string.

Throwing the keyword 'throw' instead of a value.

Throwing the type name 'int' instead of a value.

To throw an integer exception, you throw the integer value directly without quotes. Quotes would make it a string literal, which is incorrect here.

4fill in blank

hard

Fill both blanks to throw a logic_error exception with a message.

C++

throw [1]("[2] error");

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Astd::logic_error

Bruntime_error

Clogic_error

Derror

Attempts:

3 left

💡 Hint

Common Mistakes

Using the class name without the std:: prefix.

Passing a variable name instead of a string message.

Using the wrong exception class.

The std::logic_error class is used to throw logic errors. The constructor takes a string message describing the error.

5fill in blank

hard

Fill all three blanks to throw a custom exception with a message.

C++

class MyException : public std::exception {
public:
    const char* what() const noexcept override {
        return "[1]";
    }
};

throw [2](); // Throw the custom exception

// Catch block example
try {
    // code that throws
} catch (const [3]& e) {
    std::cout << e.what();
}

Drag options to blanks, or click blank then click option'

ACustom error occurred

BMyException

Dstd::exception

Attempts:

3 left

💡 Hint

Common Mistakes

Not overriding the what() method correctly.

Throwing or catching the wrong exception type.

Returning a non-string from what().

The custom exception class MyException overrides the what() method to return a custom message. We throw an object of MyException and catch it by reference.