Why exception handling is required in C++ - Test Your Understanding

Practice - 5 Tasks

1fill in blank

easy

Complete the code to catch an exception thrown by the division by zero.

C++

#include <iostream>
int main() {
    try {
        int a = 10, b = 0;
        if (b == 0) throw [1];
        std::cout << a / b << std::endl;
    } catch (int e) {
        std::cout << "Exception caught: division by zero" << std::endl;
    }
    return 0;
}

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A1

B0

Cb

Da

Attempts:

3 left

💡 Hint

Common Mistakes

Throwing a variable that is zero poorly signals an error.

Throwing the variable 'b' which is zero is not meaningful here.

Throwing an integer value like 1 is a simple way to signal an exception in C++.

2fill in blank

medium

Complete the code to handle an exception of type std::string.

C++

#include <iostream>
#include <string>
int main() {
    try {
        throw std::string("Error occurred");
    } catch ([1] e) {
        std::cout << "Caught exception: " << e << std::endl;
    }
    return 0;
}

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Aint

Bstd::string

Cfloat

Dchar

Attempts:

3 left

💡 Hint

Common Mistakes

Catching with int or char causes a mismatch and no catch.

Catching with float is incorrect for string exceptions.

The catch block must match the thrown exception type, which is std::string here.

3fill in blank

hard

Fix the error in the code by completing the catch block to handle all exceptions.

C++

#include <iostream>
int main() {
    try {
        throw 20;
    } catch ([1]) {
        std::cout << "Exception caught" << std::endl;
    }
    return 0;
}

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Afloat e

Bchar e

Cint e

D...

Attempts:

3 left

💡 Hint

Common Mistakes

Using catch(int e) only catches int exceptions.

Using catch(char e) or catch(float e) misses other types.

Using catch(...) catches any type of exception regardless of its type.

4fill in blank

hard

Fill both blanks to throw and catch a custom exception class.

C++

#include <iostream>
class MyException {
public:
    const char* what() const { return "Custom exception"; }
};
int main() {
    try {
        throw [1];
    } catch ([2]& e) {
        std::cout << e.what() << std::endl;
    }
    return 0;
}

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AMyException()

Bint

CMyException

Dstd::exception

Attempts:

3 left

💡 Hint

Common Mistakes

Throwing the class name instead of an instance causes errors.

Catching by value instead of reference can cause slicing.

Throw an instance of MyException and catch it by reference to MyException.

5fill in blank

hard

Fill all three blanks to create a try-catch block that throws an integer, catches it, and prints the value.

C++

#include <iostream>
int main() {
    try {
        throw [1];
    } catch ([2] e) {
        std::cout << "Caught value: " << [3] << std::endl;
    }
    return 0;
}

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A42

Bint

Ce

Dfloat

Attempts:

3 left

💡 Hint

Common Mistakes

Throwing a float but catching int causes mismatch.

Printing a variable not declared in catch causes errors.

Throw integer 42, catch as int, and print the caught variable e.