Lecture 5

1. COP3502: Introduction to CIS I Lecture 5

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4. updated syllabus

5. variables type, name, value declaration: inti; Assignment: inti = 5; double pi = 3.14; String name = Bob;

6. types • byte = 8-bits • short = 16-bits • int = 32-bits • long = 64-bits • float = 32-bits • double = 64-bits • boolean = not well defined • char = 16-bits

7. initial values • byte = 0 • short = 0 • int = 0 • long = 0L • float = 0.0f • double = 0.0d • boolean = false • char = “\u0000” • String = null

8. reserved keywords syntax tip: Don’t name your variable anything highlighted pink or blue by Sublime

9. loss of precision We cannot represent an infinite set of real numbers with a finite amount of memory!

10. Math class • Math.pow(x, y) • Math.sqrt(x) • Math.sin(x) • Math.log(x) • Math.abs(x) • Math.PI = 3.14….. • Math.E = 2.71…..

11. order of operations style tip: ALWAYS USE PARENTHESES x + y * z

12. order of operations style tip: ALWAYS USE PARENTHESES x + (y * z)

13. order of operations style tip: ALWAYS USE PARENTHESES “The result is ” + 5 + 10 vs. “The result is ” + (5 + 10)

14. functions

15. functions public static voidmain(Stringargs[]) public static voidnewLine() { System.out.println(); } public static voidthreeLines() { newLine(); newLine(); newLine(); }

16. parameters

17. parameters public static voidprintGreeting(Stringname) { System.out.println(“Hello, there ” + name); }

18. arguments • Math.pow(x, y) • Math.sqrt(x) • Math.sin(x) • Math.log(x) • Math.abs(x) • Math.PI = 3.14….. • Math.E = 2.71…..

19. command line arguments

20. String args[] arg[0] – first argument args[1] – second argument ….

21. if condition if (boolean condition) { // Do something }

22. if-else condition if (boolean condition) { // Do something } else { // Do something else }

23. else if condition if (boolean condition) { // Do something } else if (boolean condition) { // Do something else } else { // Do yet ANOTHER thing }