Tutorial by Examples: g

int i = 42; i = i++; /* Assignment changes variable, post-increment as well */ int a = i++ + i--; Code like this often leads to speculations about the "resulting value" of i. Rather than specifying an outcome, however, the C standards specify that evaluating such an expression produc...

int foo(void) { /* do stuff */ /* no return here */ } int main(void) { /* Trying to use the (not) returned value causes UB */ int value = foo(); return 0; } When a function is declared to return a value then it has to do so on every possible code path through it. Undefined beh...

The type of the literal Prelude> :t 1 1 :: Num a => a choosing a concrete type with annotations You can specify the type as long as the target type is Num with an annotation: Prelude> 1 :: Int 1 it :: Int Prelude> 1 :: Double 1.0 it :: Double Prelude> 1 :: Word 1 it :: ...

The type of the literal Prelude> :t 1.0 1.0 :: Fractional a => a Choosing a concrete type with annotations You can specify the type with a type annotation. The only requirement is that the type must have a Fractional instance. Prelude> 1.0 :: Double 1.0 it :: Double Prelude> 1....

#include <stdio.h> #include <stdlib.h> #include <string.h> int main(int argc, char **argv) { /* Exit if no second argument is found. */ if (argc != 2) { puts("Argument missing."); return EXIT_FAILURE; } size_t len = str...

Sets are unordered collections of unique values. Unique values must be of the same type. var colors = Set<String>() You can declare a set with values by using the array literal syntax. var favoriteColors: Set<String> = ["Red", "Blue", "Green", "Blu...

println! (and its sibling, print!) provides a convenient mechanism for producing and printing text that contains dynamic data, similar to the printf family of functions found in many other languages. Its first argument is a format string, which dictates how the other arguments should be printed as t...

Composition provides an alternative to inheritance. A struct may include another type by name in its declaration: type Request struct { Resource string } type AuthenticatedRequest struct { Request Username, Password string } In the example above, AuthenticatedRequest will con...

Any function can be invoked as a goroutine by prefixing its invocation with the keyword go: func DoMultiply(x,y int) { // Simulate some hard work time.Sleep(time.Second * 1) fmt.Printf("Result: %d\n", x * y) } go DoMultiply(1,2) // first execution, non-blocking go DoMu...

single channel, single goroutine, one write, one read. package main import "fmt" import "time" func main() { // create new channel of type string ch := make(chan string) // start new anonymous goroutine go func() { time.Sleep(time.Second) ...

The filter() method accepts a test function, and returns a new array containing only the elements of the original array that pass the test provided. // Suppose we want to get all odd number in an array: var numbers = [5, 32, 43, 4]; 5.1 var odd = numbers.filter(function(n) { return n % 2 !=...

PorterDuff.Mode is used to create a PorterDuffColorFilter. A color filter modifies the color of each pixel of a visual resource. ColorFilter filter = new PorterDuffColorFilter(Color.BLUE, PorterDuff.Mode.SRC_IN); The above filter will tint the non-transparent pixels to blue color. The color fil...

An Xfermode (think "transfer" mode) works as a transfer step in drawing pipeline. When an Xfermode is applied to a Paint, the pixels drawn with the paint are combined with underlying pixels (already drawn) as per the mode: paint.setColor(Color.BLUE); paint.setXfermode(new PorterDuffXferm...

In info.plist set View controller-based status bar appearance to YES In view controllers not contained by UINavigationController implement this method. In Objective-C: - (UIStatusBarStyle)preferredStatusBarStyle { return UIStatusBarStyleLightContent; } In Swift: override func pre...

Column aliases are used mainly to shorten code and make column names more readable. Code becomes shorter as long table names and unnecessary identification of columns (e.g., there may be 2 IDs in the table, but only one is used in the statement) can be avoided. Along with table aliases this allows ...

In order to test the beginning and ending of a given string in Python, one can use the methods str.startswith() and str.endswith(). str.startswith(prefix[, start[, end]]) As it's name implies, str.startswith is used to test whether a given string starts with the given characters in prefix. >...

NaN ("Not a Number") is a special value defined by the IEEE Standard for Floating-Point Arithmetic, which is used when a non-numeric value is provided but a number is expected (1 * "two"), or when a calculation doesn't have a valid number result (Math.sqrt(-1)). Any equality or ...

Python's str type also features a number of methods that can be used to evaluate the contents of a string. These are str.isalpha, str.isdigit, str.isalnum, str.isspace. Capitalization can be tested with str.isupper, str.islower and str.istitle. str.isalpha str.isalpha takes no arguments and retu...

try { StyledDocument doc = new DefaultStyledDocument(); doc.insertString(0, "This is the beginning text", null); doc.insertString(doc.getLength(), "\nInserting new line at end of doc", null); MutableAttributeSet attrs = new SimpleAttributeSet(); StyleCons...

try { JTextPane pane = new JTextPane(); StyledDocument doc = new DefaultStyledDocument(); doc.insertString(0, "Some text", null); pane.setDocument(doc); //Technically takes any subclass of Document } catch (BadLocationException ex) { //hand...