Strings

string is one of the most-used types in C#, but it works differently from the primitives you just learned: string is a reference type, not a primitive. A string variable doesn't store the text directly the way an int stores a number — it stores a reference to a string object living elsewhere in memory. In everyday code, though, you can create and use strings almost as easily as primitives.

string name = "Ada";
int points = 95;
Console.WriteLine("Hello, " + name + "!");
Console.WriteLine($"Score: {points}");

string comes with many useful members. Length is a property (not a method — no parentheses!) that tells you how many characters are in the string. You can also grab a single character at a given position, counting from 0, using square brackets right after the variable name.

string word = "Java";
Console.WriteLine(word.Length);   // 4
Console.WriteLine(word[0]);       // J

To find out how many characters are in a string, you read its ____ property.

The Substring(start, length) method returns a new string containing a chunk of the original: it begins at the given start position and includes exactly length characters after that.

string word = "Java";
Console.WriteLine(word.Substring(1, 2)); // av

What does "Java".Substring(1, 2) return?

Strings are immutable: once a string object is created, its contents can never change. Methods like Substring() don't modify the original string — they return a brand-new string with the result. This also means you can safely use == to compare two strings in C#: it checks their actual text content, not just whether they are the same object in memory. The .Equals() method does the same comparison and is often used interchangeably with ==.

string a = "cat";
string b = "cat";
Console.WriteLine(a == b);        // True
Console.WriteLine(a.Equals(b));   // True

In C#, the == operator compares the actual text content of two strings, not merely whether they are the exact same object.