Operator Precedence

Operator Precedence

When several operators share one expression, C needs a rule for which one runs first. That rule is precedence.

Multiplication before addition

printf("%d\n", 2 + 3 * 4);     // 14, not 20
printf("%d\n", (2 + 3) * 4);   // 20

The usual order

From highest to lowest for the operators in this course:

• *, /, %
• +, -
• ==, !=, >, <, >=, <=
• &&, then ||

Parentheses always win

If you ever feel unsure, put parentheses where you want. They override any default precedence:

printf("%d\n", (2 + 3) * 4);   // 20

Associativity: same power, left to right

For operators with equal precedence, like a - b - c, C evaluates left to right: (a - b) - c.

TL;DR

• Precedence decides which operator runs first.
• *, /, % come before +, -.
• Comparisons come after those.
• Parentheses override everything; use them when unsure.