precedence_rules - matthew9510/Studies GitHub Wiki
Precedence Rules
Java File that goes along with this wiki
An expression is a combination of items, like variables, literals, and operators, that evaluates to a value.
These expressions can sometimes get tricky depending on what is trying to be achieved.
Here are some basic things to keep in mind when evaluating expressions.
A literal is a specific value in code (e.g., 3).
Brackets [ ] or braces { } may NOT be used when calculating expressions
Integer and Double Addition and Subtraction are pretty simple and are displayed in the PrecedenceRules.java program
Integer Division
When the operands are integers, the division operator / performs integer division, throwing away any remainder.
Example:
24 / 10 - The output would be 2, where the remainder 4 would be thrown away.
1 / 2 - An expression that preforms integer division, evaluating to 0.
Note for integer division:
For integer division, the second operand of / or % must never be 0, because division by 0 is mathematically undefined. Division by 0 causes a program to terminate.
Double Division
When the operands are in the form of a double primitive data type, the division operator / performs division, keeping the remainder.
Example:
1.0 / 2.0 - An expression that preforms double division, evaluating to 0.5.
Modulo Operator
The modulo operator % evaluates to the remainder of the division of two integer operands.
Example:
24 % 10 - An expression that evaluates to 4.
10 % 10 - An expression that evaluates to 0 because 10 / 10 is 1 with a remainder 0.
1 % 2 - An expression that evaluates to 1 because 1 / 2 is 0 with a remainder 1.
Precedence Rules for arithmetic operators
It's Good practice to use parentheses to make order of evaluation explicit, rather than relying on precedence rules, as in: y = (m * x) + b, unless order doesn't matter as in x + y + z.
Arithmetic Operators
Compound Operators
Compound operators provide a shorthand way to update a variable, such as currentNum += 1 being shorthand for currentNum = currentNum + 1. Other compound operators include =, *=, /=, and %=.