Ch 5 · Operators & Expressions · C
Topic 5 of 13 in C — Complete Tutorial (Beginner) — 3 lessons.
Arithmetic Operators
Arithmetic operators perform calculations on numbers. They mostly match the symbols from maths class. The modulus operator % gives the remainder after division — 17 % 5 is 2. A crucial rule in C: dividing two integers gives an integer result with the remainder thrown away, so 7 / 2 is 3, not 3.5. To get a decimal, at least one value must be a float or double. The ++ and -- operators add or subtract one.
Comparison & Logical Operators
Comparison operators compare two values and give either 1 (true) or 0 (false) — C has no separate boolean type by default; it uses integers, where 0 means false and any non-zero value means true. Logical operators combine conditions: && (AND) needs both true, || (OR) needs at least one, and ! (NOT) flips a value. These build the conditions your program uses to make decisions.
Assignment Operators
Assignment operators are shorthand ways to update a variable using its current value. Writing score += 10 means score = score + 10. These compact forms — +=, -=, *=, /=, %= — appear constantly whenever a value changes step by step, such as counting up a score or reducing a countdown. They save typing and make the intent clear.