Precedence

Precedence gives the priority between different operator levels. Multiplication has higher precedence than addition. Therefore 2 + 3 * 4 groups as 2 + (3 * 4) and gives 14. Parentheses can change the grouping: (2 + 3) * 4 gives 20.

Associativity

Associativity decides grouping when operators have the same precedence. Multiplication and division group from left to right. Thus 20 / 5 * 2 means (20 / 5) * 2 and gives 8. Assignment groups from right to left, so a = b = 5 means a = (b = 5).

Common priority levels

1. Unary operations: Operators such as ! and unary minus group before multiplication.
2. Multiplication level: *, / and % group before addition and subtraction.
3. Comparison levels: Relational operators group before equality operators.
4. Logical levels: && groups before ||.
5. Assignment: Assignment has lower precedence than these arithmetic and logical operators. Refer to the complete table for all levels.

Important distinction

Grouping is not generally the order in which operands run. For example, multiplication grouping does not say which of two function calls runs first in f() * g(). Write separate statements when order matters. Parentheses improve readability but do not make an otherwise invalid multiple update valid.

Reference table

Key points

• Multiplication and addition must not share a precedence row.
• Relational, equality, bitwise and logical levels are distinct.