
Emphasis:


Most of the integer (arithmetic) operators should look familiar to you...
(Except for the % operator)
Operator symbol  Operation  Note 

+  addition  Binary operator, e.g.: 9 + 4 = 13 
−  subtraction  Binary operator, e.g.: 9 − 4 = 5 
*  multiplication  Binary operator, e.g.: 9 * 4 = 36 
/  division (= quotient)  Binary operator, e.g.: 9 / 4 = 2 
%  modulus (= remainder)  Binary operator, e.g.: 9 % 4 = 1 
( ... )  brackets  Changes order of computation 
−  negation 
Changes the sign of the value:
− 4 = (−4)
(Read as: − 4 = negative 4) 
The / integer operator will always produce an integer result
Examples:
9 / 4 = (floating point result = 2.25) = 2 9 / 4 = (floating point result = 2.25) = 2 9 / 4 = (floating point result = 2.25) = 2 9 / 4 = (floating point result = 2.25) = 2 
The sign of the result is always equal to the sign of the dividend
Examples:
9 % 4 = (floating point result = 2.25) = 1 9 % 4 = (floating point result = 2.25) = 1 9 % 4 = (floating point result = 2.25) = 1 9 % 4 = (floating point result = 2.25) = 1 
dividend = quotient × divisor + remainder 
Example:
9 / 4 = 2 9 % 4 = 1 9 = 2 * 4 + 1 9 / 4 = 2 9 % 4 = 1 9 = (2)* 4 + (1) 9 / 4 = 2 9 % 4 = 1 9 = (2)*(4) + 1 9 / 4 = 2 9 % 4 = 1 9 = 2 *(4) + (1) 

Special emphasis:


Operator  Priority  Note 

( .... )  Highest  
− (negation)  Higher  Unary operator, e.g.: −3 
* / %  High  Binary operator, e.g.: 4 * 5 
+ −  Lowest  Binary operator, e.g.: 4 + 5 
Operator  Associativity  Example 

( .... )  "inside out"  ((3 + 4) * 5 ) = (7 * 5) 
− (negation)  Right  − − 3 = − (−3) = 3 (from right to left) 
* / %  Left  4 * 5 % 7 / 4 = 20 % 7 / 4 = 6 / 4 = 1 
+ −  Left  4 − 6 + 4 − 7 = (−2) + 4 − 7 = 2 − 7 = −5 
Integer expression: 72 / 10 + 72 % 10 Evaluated as follows: 72 / 10 + 72 % 10 = 7 + 72 % 10 = 7 + 2 = 9 
(This is how you compute the sum of the digits in the number 72 !!!)
Integer expression: 22   3 *  4 +   1 Evaluated as follows: 22   3 *  4 +   1 = 22  (3) *  4 +   1 = 22  (3) * (4) +   1 = 22  (3) * (4) +  (1) = 22  (3) * (4) + (+1) = 22  12 + 1 (Use associativity rule) = 10 + 1 = 11 
Integer expression: (22   3) *  (4 +   1) Evaluated as follows: (22   3) *  (4 +   1) = (22  (3)) *  (4 +   1) = (22  (3)) *  (4 +  (1)) = (22  (3)) *  (4 + 1) = 25 *  (4 + 1) = 25 *  5 = 25 * (5) = 125 
How to run the program:

public class Exercise1 { public static void main(String[] args) { int a = 15; int b = 24; System.out.println(b  a + 7); System.out.println(b  a  4); System.out.println(b % a / 2); System.out.println(b % (a / 2)); System.out.println(b * a / 2); System.out.println(b * (a / 2)); System.out.println(b / 2 * a); System.out.println(b / (2 * a)); } } 
16 5 4 3 180 168 180 0 
How to run the program:


12 is divisible by 2 ⇔ 12 % 2 = 0 12 is divisible by 3 ⇔ 12 % 3 = 0 12 is divisible by 4 ⇔ 12 % 4 = 0 12 is not divisible by 5 ⇔ 12 % 5 = 2 12 is divisible by 6 ⇔ 12 % 6 = 0 12 is not divisible by 7 ⇔ 12 % 7 = 5 