Tutorial by Examples: g

An std::map takes (key, value) pairs as input. Consider the following example of std::map initialization: std::map < std::string, int > ranking { std::make_pair("stackoverflow", 2), std::make_pair("docs-beta", 1) }; In an std::...

std::map and std::multimap both can be initialized by providing key-value pairs separated by comma. Key-value pairs could be provided by either {key, value} or can be explicitly created by std::make_pair(key, value). As std::map does not allow duplicate keys and comma operator performs right to left...

Removing all elements: std::multimap< int , int > mmp{ {1, 2}, {3, 4}, {6, 5}, {8, 9}, {3, 4}, {6, 7} }; mmp.clear(); //empty multimap Removing element from somewhere with the help of iterator: std::multimap< int , int > mmp{ {1, 2}, {3, 4}, {6, 5}, {8, 9}, {3, 4}, {6, 7} }; ...

An element can be inserted into a std::map only if its key is not already present in the map. Given for example: std::map< std::string, size_t > fruits_count; A key-value pair is inserted into a std::map through the insert() member function. It requires a pair as an argument: fruits_c...

std::map or std::multimap could be traversed by the following ways: std::multimap< int , int > mmp{ {1, 2}, {3, 4}, {6, 5}, {8, 9}, {3, 4}, {6, 7} }; //Range based loop - since C++11 for(const auto &x: mmp) std::cout<< x.first <<":...

There are several ways to search a key in std::map or in std::multimap. To get the iterator of the first occurrence of a key, the find() function can be used. It returns end() if the key does not exist. std::multimap< int , int > mmp{ {1, 2}, {3, 4}, {6, 5}, {8, 9}, {3, 4}, {6, 7} }; ...

The container std::map has a member function empty(), which returns true or false, depending on whether the map is empty or not. The member function size() returns the number of element stored in a std::map container: std::map<std::string , int> rank {{"facebook.com", 1} ,{"goo...

SELECT DisplayName, JoinDate, Reputation FROM Users ORDER BY JoinDate, Reputation DisplayNameJoinDateReputationCommunity2008-09-151Jeff Atwood2008-09-1625784Joel Spolsky2008-09-1637628Jarrod Dixon2008-10-0311739Geoff Dalgas2008-10-0312567

INSERT INTO Customers (FName, LName, PhoneNumber) SELECT FName, LName, PhoneNumber FROM Employees This example will insert all Employees into the Customers table. Since the two tables have different fields and you don't want to move all the fields over, you need to set which fields to insert int...

Constructors can be created with any kinds of arguments. public class TestClass { private String testData; public TestClass(String testData) { this.testData = testData; } } Called like this: TestClass testClass = new TestClass("Test Data"); A class can ...

Each individual CSS Selector has its own specificity value. Every selector in a sequence increases the sequence's overall specificity. Selectors fall into one of three different specificity groups: A, B and c. When multiple selector sequences select a given element, the browser uses the styles appli...

Node.js package configurations are contained in a file called package.json that you can find at the root of each project. You can setup a brand new configuration file by calling: npm init That will try to read the current working directory for Git repository information (if it exists) and enviro...

The Lua standard library provides a pairs function which iterates over the keys and values of a table. When iterating with pairs there is no specified order for traversal, even if the keys of the table are numeric. for key, value in pairs(input_table) do print(key, " -- ", value) en...

Usually, Lua is being shipped with two binaries: lua - standalone interpreter and interactive shell luac - bytecode compiler Lets say we have an example program (bottles_of_mate.lua) like this: local string = require "string" function bottle_take(bottles_available) lo...

Reflection is often used as part of software testing, such as for the runtime creation/instantiation of mock objects. It's also great for inspecting the state of an object at any given point in time. Here's an example of using Reflection in a unit test to verify a protected class member contains the...

The first two arguments to format are an output stream and a control string. Basic use does not require additional arguments. Passing t as the stream writes to *standard-output*. > (format t "Basic Message") Basic Message nil That expression will write Basic Message to standard ou...

By default, containers created with docker run are given a random name like small_roentgen or modest_dubinsky. These names aren't particularly helpful in identifying the purpose of a container. It is possible to supply a name for the container by passing the --name command line option: docker run -...

docker run -p "8080:8080" myApp docker run -p "192.168.1.12:80:80" nginx docker run -P myApp In order to use ports on the host have been exposed in an image (via the EXPOSE Dockerfile directive, or --expose command line option for docker run), those ports need to be bound to...

main = do input <- getContents putStr input Input: This is an example sentence. And this one is, too! Output: This is an example sentence. And this one is, too! Note: This program will actually print parts of the output before all of the input has been fully read in. This m...

main = do line <- getLine putStrLn line Input: This is an example. Output: This is an example.