C# StringReader

last modified July 5, 2023

C# StringReader tutorial shows how to read strings in C# with StringReader.

Input & output in C# is based on streams. A Stream is an abstract base class of all streams. A stream is an abstraction of a sequence of bytes, such as a file, an input/output device, an inter-process communication pipe, or a TCP/IP socket.

C# StringReader

StringReader reads text data from strings. It can read data synchronously or asynchronously. The reading operation is stream-based.

C# StringReader ReadToEnd

The ReadToEnd method reads all characters from the current position to the end of the string and returns them as a single string.

Program.cs

using System.Text;

var sb = new StringBuilder(); sb.AppendLine(“There is a hawk in the sky.”); sb.AppendLine(“The sun is shining.”); sb.AppendLine(“The flowers are blossoming.”);

using var reader = new StringReader(sb.ToString()); string text = reader.ReadToEnd(); Console.WriteLine(text);

The example builds a string with StringBuilder and then reads the text with StringReader’s ReadToEnd.

$ dotnet run There is a hawk in the sky. The sun is shining. The flowers are blossoming.

C# StringReader ReadLine

The ReadLine method reads a line of characters from the current string and returns the data as a string.

Program.cs

var text = @“The Battle of Thermopylae was fought between an alliance of Greek city-states, led by King Leonidas of Sparta, and the Persian Empire of Xerxes I over the course of three days, during the second Persian invasion of Greece.”;

using var sr = new StringReader(text);

int count = 0; string line;

while ((line = sr.ReadLine()) != null) { count++; Console.WriteLine(“Line {0}: {1}”, count, line); }

In the example, we count the lines of a multiline string.

while ((line = sr.ReadLine()) != null) {

The ReadLine method returns the next line from the current string, or null if the end of the string is reached.

$ dotnet run Line 1: The Battle of Thermopylae was fought between an alliance Line 2: of Greek city-states, led by King Leonidas of Sparta, and the Persian Empire of Line 3: Xerxes I over the course of three days, during the second Persian invasion of Greece.

C# StringReader Read

The Read method reads the next character from the input string and advances the character position by one character.

Program.cs

var text = “There is an old hawk in the sky.”;

using var reader = new StringReader(text);

int count = 0; char mychar = ‘h’; int n;

while ((n = reader.Read()) != -1) { char c = (char) n;

if (c.Equals(mychar))
{
    count++;
}

}

Console.WriteLine($“There are {count} ‘{mychar}’ characters in the string”);

In the example, we count the occurrence of the ‘h’ character in the text.

while ((n = reader.Read()) != -1) {

The Read method returns the next character from the underlying string, or -1 if no more characters are available.

$ dotnet run There are 3 ‘h’ characters in the string

Source

StringReader class - language reference

In this article we have read strings in C# with StringReader.

Author

My name is Jan Bodnar, and I am a passionate programmer with extensive programming experience. I have been writing programming articles since 2007. To date, I have authored over 1,400 articles and 8 e-books. I possess more than ten years of experience in teaching programming.

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