Characters and Boolean Values in C++

C++ has two relatively simple, but perhaps interesting because of their daily usability, types: char (single character) and bool (true and false). Both are often used in conditions, in input, and simple on/off logic:

A char stores a single character, like a letter, number, or symbol.

#include <iostream>

int main()
{
    char letter{'A'};
    char digit{'7'};
    char symbol{'#'};

    std::cout << letter << '\n';
    std::cout << digit << '\n';
    std::cout << symbol << '\n';
}

Character literals are enclosed in single quotes. Double quotes denote a string, which is a different type, so most of the time will produce a compile error if used interchangeably.

Alternatively, you can also assign it a specific character from its numerical value, but most of the time this form is less clear than the single quote one.

#include <iostream>

int main()
{
    char character{65};

    std::cout << character << '\n';
}

A boolean can be either true or false:

#include <iostream>

int main()
{
    bool is_open{true};
    bool is_raining{false};

    std::cout << is_open << '\n';
    std::cout << is_raining << '\n';
}

Also, std::cout will print bool values as 1 (true) and 0 (false) by default. Once you get used to this it is useful, but it can be quite confusing at the beginning:

#include <iostream>

int main()
{
    char grade{'B'};
    bool passed{true};

    std::cout << "Grade: " << grade << '\n';
    std::cout << "Passed: " << passed << '\n';

    if (passed)
    {
        std::cout << "Congratulations!\n";
    }
}

A char can store a letter, a bool makes a simple choice. With good naming and initialization at definition, they all remain very readable.

Exercise: Characters and Boolean ValuesStarter code, hints and solutionOpenClose

Guided practiceBeginner · 10–15 min

Practice: Characters and Boolean Values

Work through the mission, reveal hints only when needed, and compare your result with the model solution.

Your challenge

Change grade from B to A without changing passed. Predict the character, Boolean output, and whether the congratulations branch runs.

Mission checklist

Run the starter as a baseline, then predict the change requested in Your challenge.
Make that change in your editor; use the lesson-specific hints if you need help.
Compile and run your answer, then compare with the worked solution and explain the result.

Starter program

This is the working baseline, not the completed answer. Compile as C++20, then make the change described above.

#include <iostream>

int main()
{
    char grade{'B'};
    bool passed{true};

    std::cout << "Grade: " << grade << '\n';
    std::cout << "Passed: " << passed << '\n';

    if (passed)
    {
        std::cout << "Congratulations!\n";
    }
}

Hints

Hint 1

grade holds one character in single quotes, while passed holds true or false. Without boolalpha, std::cout prints this Boolean as a number.

Hint 2

Leave passed unchanged. Edit only the single-quoted grade initializer; grade does not automatically determine whether the congratulations branch runs.

Worked solution

The text-like value in this starter is a single char, not a std::string. I changed grade from B to A. passed remains true, so it still prints as 1 and the congratulations branch still runs.

#include <iostream>

int main()
{
    char grade{'A'};
    bool passed{true};

    std::cout << "Grade: " << grade << '\n';
    std::cout << "Passed: " << passed << '\n';

    if (passed)
    {
        std::cout << "Congratulations!\n";
    }
}

Example output

Grade: A
Passed: 1
Congratulations!

Characters and Boolean Values