An expression may be a combination of multiple operators. In such expressions with the combination of multiple operators, how are the expressions evaluated ? Here a rule comes into play. Its called operator precedence. Here, the operators are grouped and each group is given a specific level of precedence.
For example:
4 + 5 * 12
Here * has higher precedence than +. Thus the evaluation would be done as follows :
4 + 5 * 12
4 + 60
64
The higher level of precedence means those operators are evaluated first in the expression. But what would happen if the expression consists of operators with same precedence level. Here again, another rule known as 'Associativity' is applied. Some may be left to right and some may be right to left.
For example, consider the following expression :
4 + 5 - 2
Here both + and - has same precedence level and there may arise a confusion how this will be evaluated. According to Associativity , + and - have left to right associativity. Thus evaluation is done as follows :
4 + 5 - 2
9 - 2
7
The following table gives the operators and their associativity: (the precedence level decreases from top to bottom). Higher the priority, the order the expression is evaluated.
For example:
4 + 5 * 12
Here * has higher precedence than +. Thus the evaluation would be done as follows :
4 + 5 * 12
4 + 60
64
The higher level of precedence means those operators are evaluated first in the expression. But what would happen if the expression consists of operators with same precedence level. Here again, another rule known as 'Associativity' is applied. Some may be left to right and some may be right to left.
For example, consider the following expression :
4 + 5 - 2
Here both + and - has same precedence level and there may arise a confusion how this will be evaluated. According to Associativity , + and - have left to right associativity. Thus evaluation is done as follows :
4 + 5 - 2
9 - 2
7
The following table gives the operators and their associativity: (the precedence level decreases from top to bottom). Higher the priority, the order the expression is evaluated.
| Operators | Description | Associativity |
|---|---|---|
| () [] . and -> ++ and -- | Function Call / Parentheses Array Subscript Member Selection Postfix Increment/Decrement | Left to Right |
| ++ and -- sizeof & * + and - ~ ! (type) |
Prefix Increment/Decrement sizeof Address of Value of Unary Plus/Minus Bitwise Complement Logical Negation Type cast | Right to Left |
| * / % | Multiplication Division Modulus | Left to Right |
| + = | Addition Subtraction | Left to Right |
| << >> | Left Shift Right Shift | Left to Right |
| < <= > >= | Less than Less than or Equals Greater than Greater than or Equals | Left to Right |
| == != | Equality Inequality | Left to Right |
| & | Bitwise AND | Left to Right |
| ^ | Bitwise XOR | Left to Right |
| | | Bitwise OR | Left to Right |
| && | Logical AND | Left to Right |
| || | Logical OR | Left to Right |
| ?: | Conditional Expression | Right to Left |
| = *= /= %= += -= <<= >>= &= ^= |= | Assigment Operators | Right to Left |
| , | Comma / Sequential Evaluation | Left to Right |
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