Character arrays in C++ - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

Output of character array initialization

What is the output of this C++ code snippet?

C++

#include <iostream>
int main() {
    char arr[] = {'H', 'e', 'l', 'l', 'o'};
    std::cout << arr << std::endl;
    return 0;
}

A H

B Compilation error

C Hello

D Random characters or garbage output

💡 Hint

Think about how C++ treats character arrays without a null terminator when printing.

The character array is not null-terminated, so printing it as a C-string leads to undefined behavior and likely garbage output.

❓ Predict Output

intermediate

Output of null-terminated character array

What will this C++ program print?

C++

#include <iostream>
int main() {
    char arr[] = "Hello";
    std::cout << arr << std::endl;
    return 0;
}

A Compilation error

B H

C Hello

D Hello\0

💡 Hint

Remember how string literals are stored in character arrays.

The string literal "Hello" includes a null terminator automatically, so printing arr outputs Hello correctly.

🔧 Debug

advanced

Identify the error in character array usage

What error will this code produce when compiled or run?

C++

#include <iostream>
int main() {
    char arr[5] = "Hello";
    std::cout << arr << std::endl;
    return 0;
}

A Prints Hell

B Compilation error: initializer string too long

C Prints Hello

D Runtime error: buffer overflow

💡 Hint

Check the size of the array vs the string literal length including null terminator.

The string "Hello" requires 6 characters including the null terminator, but the array size is only 5, causing a compilation error.

❓ Predict Output

advanced

Output after modifying character array

What is the output of this program?

C++

#include <iostream>
int main() {
    char arr[] = "Test";
    arr[2] = 'x';
    std::cout << arr << std::endl;
    return 0;
}

A Text

B Texst

C Texs

D Tex

💡 Hint

Look carefully at which character is changed and the original string.

The original string is "Test". Changing arr[2] (the third character) from 's' to 'x' results in "Text".

🧠 Conceptual

expert

Size of character array with null terminator

Given the declaration char arr[] = "Code";, what is the size of arr in bytes?

A 5

B 4

C 6

D Undefined

💡 Hint

Remember that string literals include a null terminator at the end.

The string "Code" has 4 characters plus 1 null terminator, so the array size is 5 bytes.