Tutorial by Examples: u

5.6 PHP 5.6 introduced variable-length argument lists (a.k.a. varargs, variadic arguments), using the ... token before the argument name to indicate that the parameter is variadic, i.e. it is an array including all supplied parameters from that one onward. function variadic_func($nonVariadic, ...$...

#include <stdio.h> #define SIZE (10) int main() { size_t i = 0; int *p = NULL; int a[SIZE]; /* Setting up the values to be i*i */ for(i = 0; i < SIZE; ++i) { a[i] = i * i; } /* Reading the values using pointers */ for(p =...

You can define the signing configuration to sign the apk in the build.gradle file. You can define: storeFile : the keystore file storePassword: the keystore password keyAlias: a key alias name keyPassword: A key alias password You have to define the signingConfigs block to create a signin...

You can define the signing configuration in an external file as a signing.properties in the root directory of your project. For example you can define these keys (you can use your favorite names): STORE_FILE=myStoreFileLocation STORE_PASSWORD=myStorePassword KEY_ALIAS=myKeyAlias KEY_PASSWOR...

You can store the signing information setting environment variables. These values can be accessed with System.getenv("<VAR-NAME>") In your build.gradle you can define: signingConfigs { release { storeFile file(System.getenv("KEYSTORE")) storePasswo...

There are many querying operations on maps. member :: Ord k => k -> Map k a -> Bool yields True if the key of type k is in Map k a: > Map.member "Alex" $ Map.singleton "Alex" 31 True > Map.member "Jenny" $ Map.empty False notMember is similar: &g...

The Data.Map module in the containers package provides a Map structure that has both strict and lazy implementations. When using Data.Map, one usually imports it qualified to avoid clashes with functions already defined in Prelude: import qualified Data.Map as Map So we'd then prepend Map funct...

In Normal Mode, commands can be entered by direct key combinations (typing u to undo the last change, for example). These commands often have equivalents in 'ex' mode, accessed by typing a colon :, which drops you into a single-line buffer at the bottom of the Vim window. In 'ex' mode, after typing...

Undo Command:Descriptionuu,undoUndo the most recent change5uUndo the five most recent changes (use any number) Please be aware that in Vim, the 'most recent change' varies according to the mode you are in. If you enter Insert Mode (i) and type out an entire paragraph before dropping back to Normal...

In Vim, these operations are handled differently from what you might be used to in almost any other modern editor or word processor (Ctrl-C, Ctrl-X, Ctrl-V). To understand, you need to know a little about registers and motions. Note: this section will not cover Visual Mode copying and cutting or ra...

C++11 A keyword denoting a null pointer constant. It can be converted to any pointer or pointer-to-member type, yielding a null pointer of the resulting type. Widget* p = new Widget(); delete p; p = nullptr; // set the pointer to null after deletion Note that nullptr is not itself a pointer. ...

C++11 C++11 introduced the [[noreturn]] attribute. It can be used for a function to indicate that the function does not return to the caller by either executing a return statement, or by reaching the end if it's body (it is important to note that this does not apply to void functions, since they d...

sqlite> SELECT TYPEOF(NULL); null sqlite> SELECT TYPEOF(42); integer sqlite> SELECT TYPEOF(3.141592653589793); real sqlite> SELECT TYPEOF('Hello, world!'); text sqlite> SELECT TYPEOF(X'0123456789ABCDEF'); blob

For booleans, SQLite uses integers 0 and 1: sqlite> SELECT 2 + 2 = 4; 1 sqlite> SELECT 'a' = 'b'; 0 sqlite> SELECT typeof('a' = 'b'); integer > CREATE TABLE Users ( Name, IsAdmin ); > INSERT INTO Users VALUES ('root', 1); > INSERT INTO Users VALUES ('john', 0); > S...

SQLite uses dynamic typing and ignores declared column types: > CREATE TABLE Test ( Col1 INTEGER, Col2 VARCHAR(2), -- length is ignored, too Col3 BLOB, Col4, -- no type required Col5 FLUFFY BUNNIES -- use whatever you want ); > ...

You define a keyword argument in a method by specifying the name in the method definition: def say(message: "Hello World") puts message end say # => "Hello World" say message: "Today is Monday" # => "Today is Monday" You can define multip...

2.1 Required keyword arguments were introduced in Ruby 2.1, as an improvement to keyword arguments. To define a keyword argument as required, simply declare the argument without a default value. def say(message:) puts message end say # => ArgumentError: missing keyword: message say ...

You can define a method to accept an arbitrary number of keyword arguments using the double splat (**) operator: def say(**args) puts args end say foo: "1", bar: "2" # {:foo=>"1", :bar=>"2"} The arguments are captured in a Hash. You can manip...

Returns control from a function to its caller. If return has an operand, the operand is converted to the function's return type, and the converted value is returned to the caller. int f() { return 42; } int x = f(); // x is 42 int g() { return 3.14; } int y = g(); // y is 3 If re...

A type specifier that requests the unsigned version of an integer type. When used alone, int is implied, so unsigned is the same type as unsigned int. The type unsigned char is different from the type char, even if char is unsigned. It can hold integers up to at least 255. unsigned can also be ...