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The System.Reflection namespace contains classes that allow you to obtain information about the application and to dynamically add types, values, and objects to the application.It has a module constructor that initializes a new instance of the Module class. A module is a portable executable file that has one or more classes and interfaces.Let us see an example of System.Reflection in C# −Exampleusing System; using System.Reflection; [AttributeUsage(AttributeTargets.All)] public class HelpAttribute : System.Attribute { public readonly string Url; public string Topic // Topic is a named parameter { get { return ... Read More
In Java regex matches() matches the input string against the whole string as it add a ^ and $ at the end of the input string.so it will not match the substring. So for matching substring, you should use find().Exampleimport java.util.regex.*; class PatternMatchingExample { public static void main(String args[]) { String content = "aabbcc"; String string = "aa"; Pattern p = Pattern.compile(string); Matcher m = p.matcher(content); System.out.println(" 'aa' Match:"+ m.matches()); System.out.println(" 'aa' Match:"+ m.find()); } }Output'aa' Match:false 'aa' Match:true
Dictionary is a collection of keys and values in C#. Dictionary is included in the System.Collection.Generics namespace.To create a dictionary, you first need to set it and add the key and values. Here we have added 5 keys with values to a Dictionary. We have set its keys and value type as int.IDictionary d = new Dictionary(); d.Add(1, 44); d.Add(2, 34); d.Add(3, 66); d.Add(4, 47); d.Add(5, 76);The following is the complete code −Exampleusing System; using System.Collections.Generic; public class Demo { public static void Main() { IDictionary d = new Dictionary(); d.Add(1, 44); ... Read More
Value Type and Reference, both are types in C# −Value TypeValue type variables can be assigned a value directly. They are derived from the class System.ValueType. The value types directly contain data. When you declare an int type, the system allocates memory to store the value.Value Type variables are stored in the stack.Examples are int, char, and float, which stores numbers, alphabets, and floating point numbers, respectively.Reference TypeIt refers to a memory location. Using multiple variables, the reference types can refer to a memory location. If the data in the memory location is changed by one of the variables, the ... Read More
With Java 9, new factory methods are added to Map interface to create immutable instances. These factory methods are convenience factory methods to create a collection in less verbose and in concise way.Old way to create collectionsExampleimport java.util.Collections; import java.util.HashMap; import java.util.Map; public class Tester { public static void main(String []args) { Map map = new HashMap(); map.put("A", "Apple"); map.put("B", "Boy"); map.put("C", "Cat"); Map readOnlyMap = Collections.unmodifiableMap(map); System.out.println(readOnlyMap); try { readOnlyMap.remove(0); ... Read More
To create, move and delete directories in C#, the System.IO.Directory class has methods.Firstly, import the System.IO namespace.Now, use the Director.CreateDirectory() method to create a directory in the specified path −string myDir = @"D:\NEW"; if (!Directory.Exists(myDir)) { Directory.CreateDirectory(myDir); }In the same way, you can create a sub-directory −string mysubdir = @"C:\NEW\my\"; Directory.CreateDirectory(mysubdir);
Use the param keyword to get the variable arguments in C#.Let us see an example to multiply integers. We have used params keyword to accept any number of int values −static int Multiply(params int[] b)The above allows us to find multiplication of numbers with one as well as two int values. The fllowing calls the same function with multiple values −int mulVal1 = Multiply(5); int mulVal2 = Multiply(5, 10);Let us see the complete code to understand how variable arguments work in C# −Exampleusing System; class Program { static void Main() { int mulVal1 = Multiply(5); ... Read More
Character literals are enclosed in single quotes. For example, 'x' and can be stored in a simple variable of char type. A character literal can be a plain character (such as 'x'), an escape sequence (such as '\t'), or a universal character (such as '\u02C0').Let us see an example how to define a character constant in C# −using System; namespace Demo { class Program { static void Main(string[] args) { Console.WriteLine("Welcome!\t"); Console.WriteLine("This is it!"); Console.ReadLine(); } } }Above, we ... Read More
Externalization is used whenever we need to customize serialization mechanism. If a class implements an Externalizable interface then, object serialization will be done using writeExternal() method. Whereas at receiver's end when an Externalizable object is a reconstructed instance will be created using no argument constructor and then the readExternal() method is called.If a class implements only Serializable interface object serialization will be done using ObjectoutputStream. At the receiver's end, the serializable object is reconstructed using ObjectInputStream.Below example showcases usage of Externalizable interface.Exampleimport java.io.Externalizable; import java.io.FileInputStream; import java.io.FileOutputStream; import java.io.IOException; import java.io.ObjectInput; import java.io.ObjectInputStream; import java.io.ObjectOutput; import java.io.ObjectOutputStream; public class ... Read More
First, set the two lists −List OneList < string > list1 = new List < string > (); list1.Add("A"); list1.Add("B"); list1.Add("C"); list1.Add("D");List TwoList < string > list2 = new List < string > (); list2.Add("C"); list2.Add("D");To find the difference between the two list and display the difference elements −IEnumerable < string > list3; list3 = list1.Except(list2); foreach(string value in list3) { Console.WriteLine(value); }The following is the complete example to compare two lists −Exampleusing System; using System.Collections.Generic; using System.Linq; public class Demo { public static void Main() { List < string > list1 = new ... Read More