C Booleans

Boolean Basics

C doesn't have a native bool type in traditional C (pre-C99). Instead:

• 0 means false
• non-zero means true

Using _Bool and <stdbool.h>

Starting in C99, you can use the _Bool type. If you include <stdbool.h>, you can write:

• bool – same as _Bool
• true – defined as 1
• false – defined as 0

Logical Conditions

You use boolean expressions in control structures like if, while, and logical operators:

• && – AND
• || – OR
• ! – NOT

Common Mistakes

• Confusing = with ==: if (x = 1) is assignment, not comparison!
• Using bool without including <stdbool.h>
• Assuming true or false are built-in without headers

Practice Question

What will this print?

A. 0

B. 1

C. 5

Hint: || returns 1 (true) if either side is non-zero.

Need Help?

Ask the AI if you need help understanding or want to dive deeper in any topic