Return values in C++ - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

What is the output of this function call?

Consider the following C++ code. What will be printed when foo() is called?

C++

#include <iostream>

int foo() {
    int x = 5;
    return x + 3;
}

int main() {
    std::cout << foo() << std::endl;
    return 0;
}

A 0

B 5

C Compilation error

D 8

💡 Hint

Remember the function returns the value of x plus 3.

The function foo returns 5 + 3, which is 8, so the output is 8.

❓ Predict Output

intermediate

What does this function return?

What is the return value of bar(4) in the following code?

C++

#include <iostream>

int bar(int n) {
    if (n <= 1) return 1;
    return n * bar(n - 1);
}

int main() {
    std::cout << bar(4) << std::endl;
    return 0;
}

A 24

B 10

C 1

D Compilation error

💡 Hint

This function calculates the factorial of n.

bar(4) returns 4 * 3 * 2 * 1 = 24.

❓ Predict Output

advanced

What is the output of this code with multiple return statements?

What will be printed when test() is called?

C++

#include <iostream>

int test() {
    for (int i = 0; i < 3; i++) {
        if (i == 1) return i;
    }
    return 10;
}

int main() {
    std::cout << test() << std::endl;
    return 0;
}

A 1

B 0

C 10

D Compilation error

💡 Hint

The function returns as soon as i equals 1.

The loop returns 1 when i == 1, so output is 1.

❓ Predict Output

advanced

What error does this code produce?

What error will occur when compiling this code?

C++

#include <iostream>

int f() {
    int x = 5;
    // Missing return statement
}

int main() {
    std::cout << f() << std::endl;
    return 0;
}

A No error, prints 5

B Runtime error: segmentation fault

C Warning: control reaches end of non-void function

D Syntax error: missing semicolon

💡 Hint

Functions with non-void return type must return a value.

The function f has int return type but no return statement, causing a warning.

🧠 Conceptual

expert

What is the value of x after this function call?

Given the code below, what is the value of x after modify(x) is called?

C++

void modify(int &a) {
    a = 10;
    return;
}

int main() {
    int x = 5;
    modify(x);
    return x;
}

A 5

B 10

C Compilation error

D Undefined behavior

💡 Hint

The function modifies the argument by reference.

Since modify takes a reference, it changes x to 10.