Tutorial by Examples: ros

Function-like macros

Function-like macros are similar to inline functions, these are useful in some cases, such as temporary debug log: #ifdef DEBUG # define LOGFILENAME "/tmp/logfile.log" # define LOG(str) do { \ FILE *fp = fopen(LOGFILENAME, "a"); \ ...

C Language • Preprocessor and Macros

Introspective analysis of an analyzer in C#

Create a new Console Application Add the NuGet package Microsoft.CodeAnalysis Import the namespaces Microsoft.CodeAnalysis.MSBuild, System.Linq and Microsoft.CodeAnalysis.CSharp.Syntax Write the following example code in the Main method: // Declaring a variable with the current project file ...

roslyn • Analyze source code with Roslyn

Animate an image across the Canvas

This example loads and animates and image across the Canvas Important Hint! Make sure you give your image time to fully load by using image.onload. Annotated Code <!doctype html> <html> <head> <style> body{ background-color:white; } #canvas{border:1px solid re...

html5-canvas • Animation

Measure how long something took, using elapsedMillis and elapsedMicros

#include <elapsedMillis.h> void setup() { Serial.begin(115200); elapsedMillis msTimer; elapsedMicros usTimer; long int dt = 500; delay(dt); long int us = usTimer; long int ms = msTimer; Serial.print("delay(");Serial.print(dt);Serial.println(") to...

arduino • Time Management

Cross-validation

Learning the parameters of a prediction function and testing it on the same data is a methodological mistake: a model that would just repeat the labels of the samples that it has just seen would have a perfect score but would fail to predict anything useful on yet-unseen data. This situation is call...

scikit-learn • Model selection

Order of initialization of globals across TU

Whereas inside a Translation Unit, order of initialization of global variables is specified, order of initialization across Translation Units is unspecified. So program with following files foo.cpp #include <iostream> int dummyFoo = ((std::cout << "foo"), 0); b...

C++ • Unspecified behavior

Tail Recursion Optimization Through Stack Introspection

By default Python's recursion stack cannot exceed 1000 frames. This can be changed by setting the sys.setrecursionlimit(15000) which is faster however, this method consumes more memory. Instead, we can also solve the Tail Recursion problem using stack introspection. #!/usr/bin/env python2.4 # This...

Python Language • Recursion

Macros

ShortcutDescriptionCtrl + x, (start recording a macroCtrl + x, )stop recording a macroCtrl + x, eexecute the last recorded macro

Bash • Keyboard shortcuts

Cross-site Request Forgery (CSRF) protection

Cross-site request forgery, also known as one-click attack or session riding and abbreviated as CSRF or XSRF, is a type of malicious exploit of a website where unauthorized commands are transmitted from a user that the website trusts. Learn more To enable CSRF protection, add the CsrfViewMid...

Django • Security

Using Macros to define data structures

A common use of macros is to create templates for data structures which obey common rules but may contain different fields. By writing a macro, you can allow the detailed configuration of the data structure to be specified without needing to repeat boilerplate code, nor to use a less efficient struc...

common-lisp • macros

CROSS PLATFORM DATE OBJECT

SQL Server 2012 In Transact SQL , you may define an object as Date (or DateTime) using the [DATEFROMPARTS][1] (or [DATETIMEFROMPARTS][1]) function like following: DECLARE @myDate DATE=DATEFROMPARTS(1988,11,28) DECLARE @someMoment DATETIME=DATEFROMPARTS(1988,11,28,10,30,50,123) The parameter...

Microsoft SQL Server • Dates

Cross-Site Request Forgery

Problem Cross-Site Request Forgery or CSRF can force an end user to unknowingly generate malicious requests to a web server. This attack vector can be exploited in both POST and GET requests. Let's say for example the url endpoint /delete.php?accnt=12 deletes account as passed from accnt parameter ...

PHP • Security

Using Visual Studio code to develop Cross plateform aspnet core application

With AspNetCore you can develop the application on any platform including Mac,Linux,Window and Docker. Installation and SetUp Install visual Studio Code from here Add C# extesnion Install dot net core sdk. You can install from here Now you have all the tools available. To develop the applic...

asp.net-core • Getting started with asp.net-core

Hello World for OS X (x86_64, Intel syntax gas)

.intel_syntax noprefix .data .align 16 hello_msg: .asciz "Hello, World!" .text .global _main _main: push rbp mov rbp, rsp lea rdi, [rip+hello_msg] call _puts xor rax, rax leave ret Assemble: clang main.s -o hello ./hello Not...

Assembly Language • Getting started with Assembly Language

Installation: Microsoft Windows and Linux

To install the software: After the download completes, run the installer. For Windows, the installer executable file has the .exe extension. Double-click the installer file to run it. For Linux platforms, the installer file has the .sh extension. For these platforms, you need to make ...

netbeans • Getting started with netbeans

Using string macros

String macros are syntactic sugar for certain macro invocations. The parser expands syntax like mymacro"my string" into @mymacro_str "my string" which then, like any other macro call, gets substituted with whatever expression the @mymacro_str macro returns. Base Julia com...

Julia Language • String Macros

Record and replay action (macros)

with q command we could simplify a lot of tedious work in vim. example 1. generate array sequence (1 to 20). STEP 1. press i to enter insert mode, input 1 1 STEP 2. Record following action: "append the last number to the next line, and increment the number" type esc to exit input...

vim • Macros

Add transition or Cross-fade between two images.

Step 1: Create a transition drawable in XML Save this file transition.xml in res/drawable folder of your project. <transition xmlns:android="http://schemas.android.com/apk/res/android"> <item android:drawable="@drawable/image1"/> <item android:drawable=...

Android • TransitionDrawable

Connecting with Microsoft Cognitive Services

In this example you will learn how to use Microsoft Cognitive Services with Xamarin iOS mobile application. We will use Computer Vision API to detect what is in the picture. Once you create Xamarin.iOS project please add below NuGet package to the project: https://www.nuget.org/packages/Microsoft....

Xamarin.iOS • Connecting with Microsoft Cognitive Services

Cross Product of Two Vectors

Numpy provides a cross function for computing vector cross products. The cross product of vectors [1, 0, 0] and [0, 1, 0] is [0, 0, 1]. Numpy tells us: >>> a = np.array([1, 0, 0]) >>> b = np.array([0, 1, 0]) >>> np.cross(a, b) array([0, 0, 1]) as expected. While cr...

numpy • numpy.cross