Tutorial by Examples: er

Google Perf Tools also provides a CPU profiler, with a slightly friendlier interface. To use it: Install Google Perf Tools Compile your code as usual Add the libprofiler profiler library to your library load path at runtime Use pprof to generate a flat execution profile, or a callgraph diagram...

The | can be used to have a single case statement match against multiple inputs to yield the same result: def f(str: String): String = str match { case "foo" | "bar" => "Matched!" case _ => "No match." } f("foo") // res0: String = M...

Given the following List of tuples: val pastries = List(("Chocolate Cupcake", 2.50), ("Vanilla Cupcake", 2.25), ("Plain Muffin", 3.25)) Pattern matching can be used to handle each element differently: pastries foreach { pa...

The std::nth_element algorithm takes three iterators: an iterator to the beginning, nth position, and end. Once the function returns, the nth element (by order) will be the nth smallest element. (The function has more elaborate overloads, e.g., some taking comparison functors; see the above link for...

.exr -1 gives you details about the last exception thrown. !analyze -v usually does a good job as well. For .NET, the command !pe of the SOS extension shows details about the .NET exception that was thrown.

An incomplete list of WinDbg extensions that are not installed with WinDbg itself: ExtensionPurposeSOS.NET (official Microsoft extension)SOSex.NET (extension for SOS)CoSOS.NET (extension for SOS)NetExt.NET (with focus on networking)PyKDPython scriptingPDEWindows native and store applications (stowe...

We're going to use the expression tree API to create a CalculateSalesTax tree. In plain English, here's a summary of the steps it takes to create the tree. Check if the product is taxable If it is, multiply the line total by the applicable tax rate and return that amount Otherwise return 0 ...

When static_cast is used to convert T D::* to T B::*, the member pointed to must belong to a class that is a base class or derived class of B. Otherwise the behavior is undefined. See Derived to base conversion for pointers to members

The following uses of pointer arithmetic cause undefined behavior: Addition or subtraction of an integer, if the result does not belong to the same array object as the pointer operand. (Here, the element one past the end is considered to still belong to the array.) int a[10]; int* p1 = &a...

For the built-in shift operator, the right operand must be nonnegative and strictly less than the bit width of the promoted left operand. Otherwise, the behavior is undefined. const int a = 42; const int b = a << -1; // UB const int c = a << 0; // ok const int d = a << 32; // ...

Example from the Standard, [temp.inst]/17: template<class T> class X { X<T>* p; // OK X<T*> a; // implicit generation of X<T> requires // the implicit instantiation of X<T*> which requires // the implicit instantiation of X<T**&...

Text is saved encoded (see also Strings topic) then sometimes you may need to change its encoding, this example assumes (for simplicity) that file is not too big and it can be entirely read in memory: public static void ConvertEncoding(string path, Encoding from, Encoding to) { File.WriteAllT...

This snippet is an helper function to enumerate all files older than a specified age, it's useful - for example - when you have to delete old log files or old cached data. static IEnumerable<string> EnumerateAllFilesOlderThan( TimeSpan maximumAge, ...

Basic Error Handling By default, Express will look for an 'error' view in the /views directory to render. Simply create the 'error' view and place it in the views directory to handle errors. Errors are written with the error message, status and stack trace, for example: views/error.pug html bo...

It's a good practice to run NodeJS apps controlled by process managers. Process manager helps to keep application alive forever, restart on failure, reload without downtime and simplifies administrating. Most powerful of them (like PM2) have a built-in load balancer. PM2 also enables you to manage ...

The flip flop operator .. is used between two conditions in a conditional statement: (1..5).select do |e| e if (e == 2) .. (e == 4) end # => [2, 3, 4] The condition evaluates to false until the first part becomes true. Then it evaluates to true until the second part becomes true. After t...

We can create a better mapper classes with extension methods, Suppose if i have some DTO classes like public class UserDTO { public AddressDTO Address { get; set; } } public class AddressDTO { public string Name { get; set; } } and i need to map to corresponding v...

The example is for illustration purpose of using libraries and helpers and not a valid code. Do not copy / paste it on your projects. HELPER helpers/sendEmail_helper.php if ( ! function_exists('sendEmail')) { function sendEmail($email, $subject, $message, $lang, $cc = null, $file = null) { ...

Create a new file in the application/config folder named email.php Set the parameters for sending email. These will load when you send your email. $config['newline'] = "\r\n"; //You must use double quotes on this one $config['protocol'] = 'smtp'; $config['smtp_host'] = 'ssl://smtp.gmai...

Error handling in AppleScript uses try on error. The code which may throw an error goes in the try block and any error handling code is in the on error block. The on error block is closed using end try. foo is not defined, so throws an error. When an error occurs, the dialog is displayed. try ...