Exception handling flow in C++ - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to throw an exception of type int.

C++

#include <iostream>

int main() {
    try {
        throw [1];
    } catch (int e) {
        std::cout << "Caught exception: " << e << std::endl;
    }
    return 0;
}

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A5

B"error"

C3.14

Dtrue

Attempts:

3 left

💡 Hint

Common Mistakes

Throwing a string or other type that does not match the catch block.

Forgetting to use throw keyword.

The throw statement throws an exception. Here, 5 is an int, matching the catch (int e) block.

2fill in blank

medium

Complete the code to catch exceptions of type std::string.

C++

#include <iostream>
#include <string>

int main() {
    try {
        throw std::string("error");
    } catch ([1] e) {
        std::cout << "Caught string exception: " << e << std::endl;
    }
    return 0;
}

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Achar

Bint

Cdouble

Dstd::string&

Attempts:

3 left

💡 Hint

Common Mistakes

Catching by value or wrong type causing no catch.

Using primitive types instead of std::string.

The catch block must match the thrown exception type. Here, std::string& catches the thrown std::string by reference.

3fill in blank

hard

Fix the error in the catch block to properly catch any exception.

C++

#include <iostream>

int main() {
    try {
        throw 1.23;
    } catch ([1]) {
        std::cout << "Caught an exception" << std::endl;
    }
    return 0;
}

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Aint e

Bdouble e

C...

Dchar e

Attempts:

3 left

💡 Hint

Common Mistakes

Specifying a wrong type in catch causing uncaught exceptions.

Missing catch block for thrown type.

The catch(...) block catches any exception regardless of type.

4fill in blank

hard

Fill both blanks to throw and catch a const char* exception.

C++

#include <iostream>

int main() {
    try {
        throw [1];
    } catch ([2] e) {
        std::cout << "Caught message: " << e << std::endl;
    }
    return 0;
}

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A"error occurred"

Bint

Cconst char*

Ddouble

Attempts:

3 left

💡 Hint

Common Mistakes

Throwing a string literal but catching as std::string.

Mismatched catch type causing uncaught exception.

The thrown exception is a string literal which is of type const char*. The catch block must match this type.

5fill in blank

hard

Fill all three blanks to create a map of exception types to messages using a lambda.

C++

#include <iostream>
#include <map>
#include <string>

int main() {
    std::map<std::string, std::string> errorMessages = {
        {"int", "Integer error"},
        {"double", "Double error"},
        {"string", "String error"}
    };

    auto getMessage = [&](const std::string& type) -> std::string {
        if (errorMessages.find([1]) != errorMessages.end()) {
            return errorMessages[[2]];
        } else {
            return [3];
        }
    };

    std::cout << getMessage("int") << std::endl;
    std::cout << getMessage("bool") << std::endl;

    return 0;
}

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Atype

C"Unknown error"

D"No error"

Attempts:

3 left

💡 Hint

Common Mistakes

Using wrong variable names inside the lambda.

Returning wrong default message.

The lambda checks if the type exists in the map. If yes, it returns the corresponding message; otherwise, it returns "Unknown error".