Tutorial by Examples: u

This example is written with F# in mind but the ideas are applicable in all environments The first rule when optimizing for performance is to not to rely assumption; always Measure and Verify your assumptions. As we are not writing machine code directly it is hard to predict how the compiler an...

This linker error happens, if the linker can't find a used symbol. Most of the time, this happens if a used library is not linked against. qmake: LIBS += nameOfLib cmake: TARGET_LINK_LIBRARIES(target nameOfLib) g++ call: g++ -o main main.cpp -Llibrary/dir -lnameOfLib One might also for...

The compiler can't find a file (a source file uses #include "someFile.hpp"). qmake: INCLUDEPATH += dir/Of/File cmake: include_directories(dir/Of/File) g++ call: g++ -o main main.cpp -Idir/Of/File

An interesting but rather unknown usage of Active Patterns in F# is that they can be used to validate and transform function arguments. Consider the classic way to do argument validation: // val f : string option -> string option -> string let f v u = let v = defaultArg v "Hello&quo...

F# uses the type keyword to create different kind of types. Type aliases Discriminated union types Record types Interface types Class types Struct types Examples with equivalent C# code where possible: // Equivalent C#: // using IntAliasType = System.Int32; type IntAliasType = int // ...

A container will stop if no command is running on the foreground. Using the -t option will keep the container from stopping, even when detached with the -d option. docker run -t -d debian bash

Using Derived column we can prepare the input. We will provide yyyy-MM-dd to the final conversion: Year: (DT_STR,4,1252)(DataDate / 10000) Month: (DT_STR,2,1252)(DataDate / 100 % 100) Day: (DT_STR,2,1252)(DataDate % 100) All together: (DT_DBDATE)((DT_STR,4,1252)(DataDate / 10000) + "-&q...

Using c# or vb.net code the conversion is even more simple. An output column is needed because we type can not be changed on the fly, alternative is adding an input column on forehand make it ReadWrite. Next code will fill the new column. public override void Input0_ProcessInputRow(Input0Buffer ...

int sumArrayRecursive(int * arr, int index, int arraySize) { if (index == (arraySize - 1)) { return arr[index]; } return arr[index] + sumArrayRecursive(arr, index + 1, arraySize); }

var numbers = [1,2,3,4,5]; var squares = numbers.map(function(x) { return x*x; }); // squares is [1,4,9,16,25]

var arr = [1, 2, 3, 4, 5]; var sum = arr.reduce((prev, curr) => prev + curr); console.log(sum); // Output: 15 You can also specify an initial value var arr = [1, 2, 3, 4, 5]; var sum = arr.reduce(function (previousValue, currentValue, currentIndex, array) { return previousValue + cur...

PHP is a weakly-typed language. It does not require explicit declaration of data types. The context in which the variable is used determines its data type; conversion is done automatically: $a = "2"; // string $a = $a + 2; // integer (4) $a = $a + 0.5; // ...

Although this works only for WebKit based browsers, this is helpful: /* ----------- Non-Retina Screens ----------- */ @media screen and (min-width: 1200px) and (max-width: 1600px) and (-webkit-min-device-pixel-ratio: 1) { } /* ----------- Retina Screens ----------- */ @media scre...

Classes have a local scope during definition, but functions inside the class do not use that scope when looking up names. Because lambdas are functions, and comprehensions are implemented using function scope, this can lead to some surprising behavior. a = 'global' class Fred: a = 'class' ...

Basic assembly support with gcc has the following syntax: asm [ volatile ] ( AssemblerInstructions ) where AssemblerInstructions is the direct assembly code for the given processor. The volatile keyword is optional and has no effect as gcc does not optimize code within a basic asm statement. A...

Extended asm support in gcc has the following syntax: asm [volatile] ( AssemblerTemplate : OutputOperands [ : InputOperands [ : Clobbers ] ]) asm [volatile] goto ( AssemblerTemplate : : Inp...

This attribute is used to describe the product that this particular assembly is for. Multiple assemblies can be components of the same product, in which case they can all share the same value for this attribute. [assembly: AssemblyProduct("MyProduct")]

When working with large files, you can use the System.IO.File.ReadLines method to read all lines from a file into an IEnumerable<string>. This is similar to System.IO.File.ReadAllLines, except that it doesn't load the whole file into memory at once, making it more efficient when working with l...

Ada 2012(TC-1) with Ada.Text_IO; procedure Main is type Some_Float digits 8 range 0.0 .. 10.0; X : Some_Float := 2.71; begin Ada.Text_IO.Put_Line (X'Image); end Main; Result 2.71000E+00

Ada 2012(TC-1) with Ada.Text_IO; procedure Main is type Some_Integer is range -42 .. 42; X : Some_Integer := 17; begin Ada.Text_IO.Put_Line (X'Image); end Main; Result 17