Mathematical - Relational Operators
Estimated time to read: 2 minutes
Assignment Operator¶
inti i, j;
i = 42; // i takes the value of 42
j = 21; // j takes the value of 21
i = 21; // old value overwritten. i now takes the value of 21
i = i + j; // i takes the value of 42, i + j, 21 + 21
Mathematical Operators¶
Java's mathematical operators are fairly standard.
- (
+) Addition* - (
-) Subtraction* - (
*) Multiplication - (
/) Divison - (
%) Modulus (for whole numbers)
*There are also unary versions of + and -
Precedence of binary operators, named as such because they take in two values; one on the left and one on the right, is:
Multiply, divide, modulo, add, subtract
BODMAS - Yay.
Unary Operators¶
Java has prefix and postfix increment and decrement operators
Prefix¶
Prefix increment (++i) increments i by 1 and the uses it in the expression. Prefix decrement (--i) decrement i by 1 and the uses it in the expression.
Postfix¶
Postfix increment (i++) uses i in the expression and the increments it by 1. Postfix decrement (i--) uses i in the expression and then decrements it by 1.
Example of usage¶
Using i as an array index. Do you want to:
Increment the array index first, then use the incremented value. ++i
Or use the value first and then increment if for a subsequent use. i++
Relational Operators¶
Java has the following relational operators:
| Relational Operator | Example | Comparison meaning |
|---|---|---|
| < | a < b | a is less than b |
| <= | a <= b | a is less than or equal to b |
| == | a == b | a is equal to be |
| != | a != b | a is not equal to b |
| >= | a >= b | a is greater than or equal to b |
| > | a > b | a is greater than b |
The operators result in a boolean value (true / false) which is normally used in branching or looping statements.