Try–catch block in C++ - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

Output of try–catch with integer exception

What is the output of this C++ code?

C++

#include <iostream>

int main() {
    try {
        throw 5;
    } catch (int e) {
        std::cout << "Caught integer: " << e << std::endl;
    }
    return 0;
}

A Caught integer: 0

B Caught integer: 5

C No output

D Compilation error

💡 Hint

The throw statement throws an integer, which is caught by the catch block.

The try block throws an integer 5. The catch block catches an int and prints it.

❓ Predict Output

intermediate

Output when no exception is thrown

What will this C++ program output?

C++

#include <iostream>

int main() {
    try {
        std::cout << "Inside try block" << std::endl;
    } catch (...) {
        std::cout << "Caught exception" << std::endl;
    }
    std::cout << "After try-catch" << std::endl;
    return 0;
}

A

Inside try block
After try-catch

B Compilation error

C Inside try block

D

Caught exception
After try-catch

💡 Hint

No exception is thrown, so catch block is skipped.

Since no exception is thrown, the catch block is not executed. Both print statements run.

❓ Predict Output

advanced

Output with multiple catch blocks

What is the output of this C++ code?

C++

#include <iostream>

int main() {
    try {
        throw 'a';
    } catch (int e) {
        std::cout << "Caught int: " << e << std::endl;
    } catch (char e) {
        std::cout << "Caught char: " << e << std::endl;
    } catch (...) {
        std::cout << "Caught unknown exception" << std::endl;
    }
    return 0;
}

A Compilation error

B Caught int: 97

C Caught unknown exception

D Caught char: a

💡 Hint

The thrown type is char, so the matching catch block runs.

The throw statement throws a char 'a'. The catch block for char catches it and prints it.

❓ Predict Output

advanced

Exception not caught by specific catch block

What happens when this C++ code runs?

C++

#include <iostream>

int main() {
    try {
        throw 3.14;
    } catch (int e) {
        std::cout << "Caught int: " << e << std::endl;
    }
    return 0;
}

A Program terminates with uncaught exception

B Caught int: 3

C Caught int: 3.14

D Compilation error

💡 Hint

The thrown type is double but catch expects int.

The thrown double 3.14 is not caught by catch(int), so the exception is uncaught and program terminates.

🧠 Conceptual

expert

Behavior of nested try–catch blocks

Consider this C++ code with nested try–catch blocks. What is the output?

C++

#include <iostream>

int main() {
    try {
        try {
            throw 10;
        } catch (double e) {
            std::cout << "Inner catch double" << std::endl;
        }
    } catch (int e) {
        std::cout << "Outer catch int: " << e << std::endl;
    }
    return 0;
}

A No output

B Inner catch double

C Outer catch int: 10

D Compilation error

💡 Hint

The inner catch does not catch int, so exception propagates to outer catch.

The inner try throws int 10, inner catch expects double so it does not catch. Exception goes to outer catch which catches int and prints it.