C++ · Chapter 14 of 49
C++ Booleans
The `bool` type holds one of two values: `true` or `false`, internally stored as 1 or 0. Booleans are the result of comparisons and are used to control the flow of a program.
Any non-zero number is treated as true when converted to bool, and zero is treated as false — this matters when mixing numbers and conditions.
Boolean values
`bool isReady = true;` declares a boolean. Comparisons like `5 > 3` automatically produce a bool result.
Truthy conversions
In an `if` condition, any non-zero int is treated as true. This is a common source of subtle bugs when a variable is accidentally used instead of a real comparison.
Example 1 (cpp)
bool isOpen = true;
std::cout << isOpen;Output
1true prints as 1 by default with cout.
Example 2 (cpp)
int x = 5;
if (x) std::cout << "truthy";Output
truthyNon-zero integers are treated as true in conditions.
Key points
- bool holds true or false, stored as 1 or 0.
- Comparisons produce bool results.
- Non-zero values are truthy in conditions.
- std::boolalpha can make cout print 'true'/'false' as words.
💡 Note: Use `std::cout << std::boolalpha << isOpen;` to print 'true' instead of 1.