C++ Booleans

Boolean (bool) is a data type that can store only two values: true or false. It is used to represent logical conditions or binary states in a program.

• Internally, true is represented as 1 and false as 0, so boolean values can be used in arithmetic expressions.
• Integer or floating-point values can be implicitly converted to bool (0 becomes false and any non-zero value becomes true).

#include <iostream>
using namespace std;

int main()
{
    int a = 10, b = 20;

    // Boolean variables
    bool isEqual = (a == b);
    bool isSmaller = (a < b);

    cout << "Is a equal to b? " << isEqual << endl;
    cout << "Is a smaller than b? " << isSmaller << endl;

    // Using bool in if statement
    if (isSmaller) 
        cout << "a is smaller than b" << endl;
    else 
        cout << "a is not smaller than b" << endl;

    return 0;
}

Is a equal to b? 0
Is a smaller than b? 1
a is smaller than b

Important Points

1. The default numeric value of true is 1 and false is 0.

2. We can use bool-type variables or values true and false in mathematical expressions also. For instance,

int x = false + true + 6;

It is valid and the expression on the right will evaluate to 7 as false has a value of 0 and true will have a value of 1.

3. It is also possible to convert implicitly the data type integers or floating point values to bool type. 

Example:

bool x = 0;  // false
bool y = 100;  // true
bool z = 15.75;  // true

5. The most common use of the bool datatype is for conditional statements. We can compare conditions with a boolean, and also return them telling if they are true or false.