golang

Exercises from the book "The Go Programming Language"

Questions

• X := 10 * time.Second

1. Tutorial

Program	Purpose
a_helloworld	the classic with unicode possible
b_echo1	echo with for i++ loop
c_echo2	echo with for range loop
d_echo3	echo with strings.Join
e_exercise-1.2	echo with index printed
f_exercise-1.3	Benchmark string concat vs join
g_dup1	check dup lines with bufio.NewScanner
h_dup2	bufio.NewScanner now takes *os.File args
i_dup3	read files at once with ioutil.ReadFile
j_exercise-1.4	dup with print filename from map[string]string
k_lissajous	GIF animation with scifi sinus waves
l_fetch	curl with a few lines
m_exercise-1.7	fetch using io.Copy to stdout
n_exercise-1.7b	fetch auto adding http prefix to url
o_exercise-1.9	fetch printing http status code additionaly
p_fetchall	fetch in parallel with goroutines
q_exercise-1.10	fetchall with writing contents to files
r_server1	web server doing simple echo
s_server2	web server with request count wieth Mutex
t_server3	web server printing headers and other http infos
u_server-gif	web server sending GIF from k_lissajous

2. Program Structure

Program	Purpose
a_retpointer	returning a pointer to local var (escape analysis)
b_echo4	echo with flag.Parse()
c_cf	celsius fahrenheit type conversion using package tempconv
d_bitlevel	shift and mask on binary numbers
popcount	counting number of bits set to 1 in a word
tempconv	celsius fahrenheit type conversion package

3. Basic Data Types

Program	Purpose
a_surface	creating a SVG graphic with float calculations
b_exercise-3.3	adding color gradient from red to blue
c_surfserver	serving svg via http server

4. Composite Types

Program	Purpose
a_sha256	printf sha256 sums of type [32]byte with %x
b_exercise-4.1	counting the bits set diffently in two sha256 sums
c_exercise-4.2	reading all STDIN and printing the sha256 sum of it
d_rev	reverse a slice
e_exercise-4.3	reverse array [6]int
f_exercise-4.4	left rotate a slice
g_exercise-4.5	remove adjacent duplicates from string slice
h_exercise-4.6	in place squash unicode spaces into ascii space
i_charcount	charcount NewReader(STDIN) ReadRune()
j_charclass	count character classes
k_wordfreq	count word frequencies with NewScanner / Split ScanWords
l_github	github json api client with structs
m_issues	command line issue search for github
n_exercise-4.10	classify github issues search results by age new or old
o_exercise-4.13	command line client for movie poster download
p_issuesreport	issue rendering with text template
q_issueshtml	issue rendering with html template
r_exercise-4.14	web server rendering html issue info

5. Functions

Program	Purpose
a_findlinks	parse html (stdin) and find links
b_exercise-5.1	findlinks without for loop
c_exercise-5.2	count types of element nodes in map
d_exercise-5.3	parse html TextNodes and print to stdout
e_exercise-5.4	findlinks1 + additionally find other links like images and scripts
f_outline2	print outline of a parsed html tree from url
g_exercise-5.7	pretty printing the parsed html
h_exercise-5.8	implemented getElementById on parsed html tree
i_exercise-5.9	expanding $foo with function argument

6. Methods

Program	Purpose
a_intset	set of small integers implemented as Bit Vector
b_exercise-6.1	added some methods
c_exercise-6.2	added variadic AddAll Method
d_exercise-6.3	added Intersect and Difference Methods
e_exercise-6.4	added Elems Method returning slice for range loop

7. Interfaces

Program	Purpose
a_exercise-7.1	LineCounter and WordCounter implementing the Writer interface
b_exercise-7.2	CountingWriter returns a Wrapper to a given io.Writer + *counter
c_exercise-7.3	added String Method to tree type
d_exercise-7.4	reimplement strings.NewReader
f_tempflag	tempconv command line - celsiusFlag satisfies flag.Value interface
g_exercise-7.9	html table using sort.Interface
h_exercise-7.11	update func adapted to http.Handler interface using DefaultServeMux
i_eval	expression evaluator
j_exercise-7.13	add String method to Expr interface
k_xmlselect	print the text of xml elements selected py path
l_exercise-7.17	xmlselect also by attributes
m_exercise-7.18	constructing a tree of generic nodes from xml tokens

8. Goroutines and Channels

Program	Purpose
a_exercise-8.1	clock server and clients with goroutines
b_exercise-8.2	FTP Server
c_exercise-8.3	netcat3 -> *net.TCPConn.CloseWrite()
d_exercise-8.4	using sync.WaitGroup to count the number of active echo goroutines
e_exercise-8.8	echoserver now has timeout using select statement
f_exercise-8.9	du status updates now seperate for each root
g_chatserver	a server broadcasting chat messages to all tcp clients like netcat
h_exercise-8.12	announce set of clients to new arrivals
i_exercise-8.13	added timeout to chat server
j_exercise-8.14	chat servers network protocol now asks for user name

9. Concurrency With Shared Variables

Program	Purpose
a_exercise-9.1	withdraw added to bank1
b_exercise-9.5	found limit of ~ 2.5 mio goroutines with 8GB Memory
c_exercise-9.6	found limit of ~ 4.5 mio messages per second