Math Functions

Math Operators

•      Addition (+)
•      Subtraction (-)
•      Multiplication (*)
•      Division (/)
•      Modulo (%) – the remainder. 7%2 = 1. 5%5 = 0. 5%0 is undefined.
•      String Concatenation (+) – “cat” + “mat” = “catmat”
•      Increment (++) – eg. i++ takes what is in i and adds one to it
•      Decrement (--) – eg. i-- takes what is in i and subtracts one from it

An interesting math function is pulling out the digits of a number. To do this, you need to use a combination of divide and mod.

public class ParseDigits
{
   public static void main (String args [])
   {new ParseDigits();
   }


	public ParseDigits()
	{
     int number = 123;
     int digit1 = number/100;
     int digit2 = (number - (digit1*100))/10;
     int digit3 = number%10;
     System.out.println(digit1+" "+digit2+" "+digit3);

   }
}

Order of Operations

Java order of operations is something like BEDMAS in math. It is a little more involved than the BEDMAS rule because there are more operators than brackets, exponents etc.

This is not a complete list of operators. It is in order from performed first to performed last. You are advised to use brackets to show the order and not rely on the order of operation. Brackets make the code easier to read.

• Left-associative operators of the same precedence are evaluated in order from left to right. In the expression 10-4+2, the subtraction is done first because it is to the left of the addition, producing a value of 8.