Shorthand operators

Shorthand operators Shorthand operator: A shorthand operator is a shorter way to express something that is already available in the Java programming language Shorthand operations do not add any feature to the Java programming language (So it's not a big deal).

Shorthand operators +=, -=, *=, /= and *= A frequent construct is the following: Java has a shorthand operator for these kinds of assignment statements x is a variable in the program x = x + value ; // Add value to the variable x x = x - value ; // Subtract value to the variable x x = x * value ; // Increase the variable x by value times and so on...

Shorthand operators +=, -=, *=, /= and *= (cont.) Operator assignment short hands:  Operator symbol   Name of the operator  Example   Equivalent construct  +=   Addition assignment  x += 4;  x = x + 4; -=   Subtraction assignment  x -= 4;  x = x - 4; *=   Multiplication assignment  x *= 4;  x = x * 4;   /=   Division assignment  x /= 4;  x = x / 4; %=   Remainder assignment  x %= 4;  x = x % 4;

Shorthand operators +=, -=, *=, /= and *= (cont.) Exercise: what is printed by the following program public class Shorthand1 { public static void main(String[] args) int x; x = 7; x += 4; System.out.println(x); x -= 4;

Shorthand operators +=, -=, *=, /= and *= (cont.) x = 7; x *= 4; System.out.println(x); x /= 4; x %= 4; }

Shorthand operators +=, -=, *=, /= and *= (cont.) Example Program: (Demo above code) Prog file: http://mathcs.emory.edu/~cheung/Courses/170/Syllabus/04/Progs/Shorthand1.java How to run the program:             Right click on link and save in a scratch directory To compile:   javac Shorthand1.java To run:          java Shorthand1 (You will see the answers on the terminal)

Increment and decrement shorthand operators Two very commonly used assignment statements are: Java has shorthand operators to increment and decrement a variable by 1 (one). 1. x = x + 1; and 2. x = x - 1; x is a variable in the program

Increment and decrement shorthand operators (cont.) Increment and decrement operators:  Operator symbol    Name of the operator  Example   Equivalent construct  ++ Increment  x++; x = x + 1; -- Decrement x--; x = x - 1;

Increment and decrement shorthand operators (cont.) Exercise: what is printed by the following program public class Shorthand2 { public static void main(String[] args) int x; x = 7; x++; System.out.println(x); x--; }

Increment and decrement shorthand operators (cont.) Example Program: (Demo above code) Prog file: http://mathcs.emory.edu/~cheung/Courses/170/Syllabus/04/Progs/Shorthand2.java How to run the program:             Right click on link and save in a scratch directory To compile:   javac Shorthand2.java To run:          java Shorthand2 (You will see the answers on the terminal)