Introduction
Strings are a sequence of characters enclosed within double-quotes. It represents an array of characters under a single variable. The difference between a character array and a string is that in a character array, the size has to be allotted at the time of declaration and cannot be altered at run time. However, in strings, there is no need to specify the size to allocate fixed memory at the time of declaration.
Every program uses strings for various purposes. In C#, String is a part of the System.String class. It provides different methods to manipulate strings according to the programmer’s choice.
Strings
Creation
We use the string keyword to declare a string variable and initialise the value within double-quotes.
using System;
namespace CsString {
class NewString {
public static void Main(string [] args) {
// create string
string str = "Hello World";
// print string
Console.WriteLine("Programming with C#");
Console.WriteLine(str1);
Console.ReadLine();
}
}
}
Output:
Programming with C#
Hello WorldImmutable and mutable strings
Strings are immutable, i.e. they cannot be changed once created. This means that every time we try to modify the string, a new string object is created in place of the original. The initial string str is concatenated with another string to create a new string object.
using System;
namespace CsString {
class CString {
public static void Main(string [] args) {
string str = "Hello";
Console.WriteLine(str);
str = string.concat(str, " WORLD");
Console.WriteLine(str);
Console.ReadLine();
}
}
}
Output:
Hello
Hello World
Mutable strings can be modified dynamically without creating a new string object. These strings are created using the StringBuilder class. The Append method combines two strings.
using System;
using System.Text;
namespace CsString {
class NewString {
public static void Main(string [] args) {
StringBuilder str = new StringBuilder("Hello");
str.Append(" World");
Console.WriteLine(str);
Console.ReadLine();
}
}
}
Output:
Hello World
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