Google Go illustrated on the basis of Fibonacci numbers

Transcription

1 Google Go illustrated on the basis of Fibonacci numbers Jan Pennekamp RWTH University Aachen Chair for Data Management and Data Exploration Prof. Dr. T. Seidl Supervision: Dipl.-Ing. Marwan Hassani Friday, 29st June 2012 slide 1 of 30 Jan Pennekamp Google Go illustrated on the basis of Fibonacci numbers

2 1 Introduction 2 Basics about Go 3 Example: Fibonacci numbers 4 Conclusion 5 Bibliography 6 Additional slide 2 of 30 Jan Pennekamp Google Go illustrated on the basis of Fibonacci numbers

3 Main developers Ken Thompson * 1943 Unix shell B (programming language) UTF-8 slide 3 of 30 Jan Pennekamp Google Go illustrated on the basis of Fibonacci numbers

4 Main developers Ken Thompson * 1943 Rob Pike * 1956 Unix shell B (programming language) UTF-8 Plan 9 (operating system) UTF-8 slide 3 of 30 Jan Pennekamp Google Go illustrated on the basis of Fibonacci numbers

5 Go s goals today s C secure fast to compile easy to code slide 4 of 30 Jan Pennekamp Google Go illustrated on the basis of Fibonacci numbers

6 Go s goals today s C secure fast to compile easy to code for every project and environment slide 4 of 30 Jan Pennekamp Google Go illustrated on the basis of Fibonacci numbers

7 Go s goals today s C secure fast to compile easy to code for every project and environment => advantages of imperative and dynamic programming slide 4 of 30 Jan Pennekamp Google Go illustrated on the basis of Fibonacci numbers

8 History of Go open source project financed by Google slide 5 of 30 Jan Pennekamp Google Go illustrated on the basis of Fibonacci numbers

9 History of Go open source project financed by Google initial design public release TIOBE award 09 Sep Nov Jan used at Google Go 1 release May 2010 Mar slide 5 of 30 Jan Pennekamp Google Go illustrated on the basis of Fibonacci numbers

10 Influences on Go slide 6 of 30 Jan Pennekamp Google Go illustrated on the basis of Fibonacci numbers

11 Recent release: Go1 Windows compiler final syntax stable converter for Go to Go1 code slide 7 of 30 Jan Pennekamp Google Go illustrated on the basis of Fibonacci numbers

12 Hello World 1 // Hello World program in Google Go 2 package main 3 4 import " fmt " 5 6 func main () { 7 fmt. Println (" Hello world ") 8 } slide 8 of 30 Jan Pennekamp Google Go illustrated on the basis of Fibonacci numbers

13 Built-in data types Integer int8, int16, int32, uint8,... Float float32, float64 Other complex64, complex128, string, char, uchar Boolean bool slide 9 of 30 Jan Pennekamp Google Go illustrated on the basis of Fibonacci numbers

14 Built-in data types Integer int8, int16, int32, uint8,... Float float32, float64 Other complex64, complex128, string, char, uchar Boolean bool structs anonymous structs collections slide 9 of 30 Jan Pennekamp Google Go illustrated on the basis of Fibonacci numbers

15 Loops implemented in Go only for loops slide 10 of 30 Jan Pennekamp Google Go illustrated on the basis of Fibonacci numbers

16 Loops implemented in Go only for loops 1 // regular for loop 2 for i := 0; i < 10; i++ {... } 3 4 // while loop 5 for ; sum < 1000; {... } 6 for sum < 1000 {... } 7 8 // infinite loop 9 for ; ; {... } 10 for true {... } 11 for {... } slide 10 of 30 Jan Pennekamp Google Go illustrated on the basis of Fibonacci numbers

17 Control structures complex switch command break, continue GoTo (contradiction to Go s goals) slide 11 of 30 Jan Pennekamp Google Go illustrated on the basis of Fibonacci numbers

18 Miscellaneous pointer used for cbv, cbr no real pointer aritmetic garbage collector slide 12 of 30 Jan Pennekamp Google Go illustrated on the basis of Fibonacci numbers

19 Miscellaneous pointer used for cbv, cbr no real pointer aritmetic garbage collector package system, interfaces godoc, gofmt slide 12 of 30 Jan Pennekamp Google Go illustrated on the basis of Fibonacci numbers

20 Overview important example in computer science Pascal & Java commonly known slide 13 of 30 Jan Pennekamp Google Go illustrated on the basis of Fibonacci numbers

21 Overview important example in computer science Pascal & Java commonly known both with influence on Go slide 13 of 30 Jan Pennekamp Google Go illustrated on the basis of Fibonacci numbers

22 Overview important example in computer science Pascal & Java commonly known both with influence on Go shows advantages and easyness of Go slide 13 of 30 Jan Pennekamp Google Go illustrated on the basis of Fibonacci numbers

23 If-else chains 1 // if - else chain - exception handling 2 switch { 3 case n <= 0: 4 return 0, 1, err. New (" Number lower / equal zero, try again.") 5 case n >= 100: 6 return 0, 1, err. New (" Number higher / equal 100, try again.") 7 } slide 14 of 30 Jan Pennekamp Google Go illustrated on the basis of Fibonacci numbers

24 Multiple return values 1 // function declaration 2 func fib (a, b int64, n int ) ( int64, int64, error ) { 3 // name parameters return values 4 5 // function call 6 _,res, err := fib (0,1,n) 7 // return values name parameters slide 15 of 30 Jan Pennekamp Google Go illustrated on the basis of Fibonacci numbers

25 Multiple assignments 1 // multiple assignments in Go 2 b, a = a+b, b 3 // uses the values of the variables before the call slide 16 of 30 Jan Pennekamp Google Go illustrated on the basis of Fibonacci numbers

26 Rating advantages: keeps it goals has a future in development modern language slide 17 of 30 Jan Pennekamp Google Go illustrated on the basis of Fibonacci numbers

27 Rating advantages: keeps it goals has a future in development modern language disadvantages: assoziated with Google hardly literature slide 17 of 30 Jan Pennekamp Google Go illustrated on the basis of Fibonacci numbers

28 Own opinion easy to learn for every project fast compile time has a future slide 18 of 30 Jan Pennekamp Google Go illustrated on the basis of Fibonacci numbers

29 Own opinion easy to learn for every project fast compile time has a future => good requirements to become today s C slide 18 of 30 Jan Pennekamp Google Go illustrated on the basis of Fibonacci numbers

30 Additional features goroutines channels native network support... slide 19 of 30 Jan Pennekamp Google Go illustrated on the basis of Fibonacci numbers

31 Questions Thank you for your attention! Any questions? slide 20 of 30 Jan Pennekamp Google Go illustrated on the basis of Fibonacci numbers

32 Bibliography - Books books: Ivo Balbaert. The Way to Go - A Thorough Introduction to the Go Programming Language Rainer Feike and Steffen Blass. Programmierung in Google Go Frank Müller. Systemprogrammierung in Google Go - Grundlagen- Skalierbarkeit- Performanz- Sicherheit slide 21 of 30 Jan Pennekamp Google Go illustrated on the basis of Fibonacci numbers

33 Bibliography - Books internet: slide 22 of 30 Jan Pennekamp Google Go illustrated on the basis of Fibonacci numbers

34 Structs 1 type example struct { 2 number int 3 name string 4 } var ( 7 valuea example = example {1, " one "} 8 valueb example = example {2, " two "} 9 ) slide 23 of 30 Jan Pennekamp Google Go illustrated on the basis of Fibonacci numbers

35 Package import 1 import ( 2. " fmt " 3 err " errors " 4 ) err. New (" Number lower / equal zero, try again.") Printf (" The fibonacci number of %v is %v\n",n, res ) slide 24 of 30 Jan Pennekamp Google Go illustrated on the basis of Fibonacci numbers

36 Google Go version 1 package main 2 // package i m p o r t 3 i m p o r t ( 4. fmt 5 e r r e r r o r s 6 ) 7 8 // f u n c t i o n w i t h 3 r e t u r n v a l u e s 9 f u n c f i b ( a, b i n t 6 4, n i n t ) ( i n t 6 4, i n t 6 4, e r r o r ) { 10 // i f e l s e chain exception handling 11 s w i t c h { 12 case n <= 0 : 13 r e t u r n 0, 1, e r r. New( Number l o w e r / e q u a l zero, t r y a g a i n. ) 14 case n >= 100: 15 r e t u r n 0, 1, e r r. New( Number h i g h e r / e q u a l 100, t r y a g a i n. ) 16 } 17 // c a l c u l a t i o n 18 f o r i := i n t ( b ) ; i < n ; i++ { 19 b, a = a+b, b 20 } 21 r e t u r n a, b, n i l 22 } slide 25 of 30 Jan Pennekamp Google Go illustrated on the basis of Fibonacci numbers

37 Google Go version (continuation) 1 // main p r o c e d u r e 2 f u n c main ( ) { 3 v a r n i n t 4 f. P r i n t f ( This program c a l c u l a t e s t h e f i b o n a c c i numbers i t e r a t i v e.\ n ) 5 // w h i l e l o o p 6 f o r { 7 f. P r i n t f ( Which f i b o n a c c i number s h o u l d be computed?\n ) 8 f. Scanf ( %d, &n ) 9 // f u n c t i o n c a l l 10, r e s, e r r := f i b ( 0, 1, n ) 11 i f e r r!= n i l { 12 f. P r i n t l n ( e r r ) // e r r o r o u tput 13 } e l s e { 14 f. P r i n t f ( The f i b o n a c c i number o f %v i s %v\n, n, r e s ) // r e s u l t o u t p u t 15 } 16 } 17 } 18 // 707 c h a r a c t e r s w i t h o u t comments slide 26 of 30 Jan Pennekamp Google Go illustrated on the basis of Fibonacci numbers

38 Java version 1 p u b l i c c l a s s F i b o n a c c i { 2 // f u n c t i o n 3 p u b l i c s t a t i c l o n g f i b ( i n t n ) 4 throws FibonacciNegativeException, FibonacciTooBigException { 5 // i f e l s e chain exception handling 6 i f ( n <= 0) 7 throw new F i b o n a c c i N e g a t i v e E x c e p t i o n ( ) ; 8 i f ( n >= 100) 9 throw new FibonacciTooBigException ( ) ; 10 // c a l c u l a t i o n 11 l o n g a = 0, b = 1, c ; 12 f o r ( i n t i = 2 ; i <= n ; i ++) { 13 c = a + b ; 14 a = b ; 15 b = c ; 16 } 17 r e t u r n b ; 18 } slide 27 of 30 Jan Pennekamp Google Go illustrated on the basis of Fibonacci numbers

39 Java version (continuation) 1 // main p r o c e d u r e 2 p u b l i c s t a t i c v o i d main ( S t r i n g [ ] a r g s ) { 3 System. out. p r i n t l n ( This program c a l c u l a t e s t h e f i b o n a c c i numbers i t e r a t i v e. ) ; 4 // w h i l e l o o p 5 w h i l e ( t r u e ) { 6 System. out. p r i n t l n ( Which f i b o n a c c i number s h o u l d be computed? ) ; 7 i n t n =I n t e g e r. p a r s e I n t ( System. c o n s o l e ( ). r e a d L i n e ( ) ) ; 8 System. out. p r i n t l n ( ) ; 9 // r e s u l t o u t p u t 10 t r y { System. out. p r i n t l n ( The f i b o n a c c i number o f + n + i s + f i b ( n ) ) ; } 11 catch ( FibonacciNegativeException fne ) // e r r o r output 12 {System. out. p r i n t l n ( Number l o w e r / e q u a l zero, t r y a g a i n. ) ;} 13 catch ( FibonacciTooBigException ftbe ) // e r r o r output 14 {System. out. p r i n t l n ( Number h i g h e r / e q u a l 100, t r y a g a i n. ) ;} 15 System. out. p r i n t l n ( ) ; 16 } 17 } 18 } 19 // 1020 c h a r a c t e r s w i t h o u t comments slide 28 of 30 Jan Pennekamp Google Go illustrated on the basis of Fibonacci numbers

40 Pascal version 1 PROGRAM f i b o n a c c i ; 2 USES c r t ; // package i m p o r t 3 VAR n : INTEGER ; 4 re s : LONGINT ; 5 6 // f u n c t i o n 7 FUNCTION F i b o n a c c i ( n : INTEGER) : LONGINT ; 8 VAR i : INTEGER ; 9 a, b, c : LONGINT ; 10 BEGIN 11 // c a l c u l a t i o n 12 a := 0 ; b := 1 ; 13 FOR i := 2 TO n DO 14 BEGIN 15 c := a + b ; 16 a := b ; 17 b := c ; 18 END; 19 Fibonacci := b ; 20 END; slide 29 of 30 Jan Pennekamp Google Go illustrated on the basis of Fibonacci numbers

41 Pascal version (continuation) 1 // main p r o c e d u r e 2 BEGIN 3 W r i t e l n ( This program c a l c u l a t e s t h e f i b o n a c c i numbers i t e r a t i v e. ) ; 4 // w h i l e l o o p 5 WHILE ( t r u e ) DO 6 BEGIN 7 REPEAT 8 W r i t e l n ( Which f i b o n a c c i number s h o u l d be computed? ) ; 9 Readln ( n ) ; 10 // e x c e p t i o n h a n d l i n g 11 IF ( n <= 0) 12 THEN W r i t e l n ( Number l o w e r / e q u a l zero, t r y a g a i n. ) 13 ELSE IF ( n >= 100) 14 THEN W r i t e l n ( Number h i g h e r / e q u a l 100, t r y a g a i n. ) ; 15 UNTIL ( n > 0) AND ( n < 100) ; 16 Writeln ; 17 // f u n c t i o n c a l l 18 r e s := F i b o n a c c i ( n ) ; 19 W r i t e l n ( The f i b o n a c c i number o f, n, i s, r e s ) ; // r e s u l t o u t p u t 20 Writeln ; 21 END; 22 END. 23 // 760 c h a r a c t e r s w i t h o u t comments slide 30 of 30 Jan Pennekamp Google Go illustrated on the basis of Fibonacci numbers