Input and Output
Input and output operations in C# are essential for interacting with users, reading data from external sources, and displaying information to the user. C# provides various classes and methods to handle input and output efficiently. Here are the key aspects of input and output in C#:
Console Input and Output:
- The Console class provides methods for reading input from the user and writing output to the console.
- WriteLine() is used to display output on the console.
- ReadLine() is used to read a line of text input from the user.
Example:
Console.WriteLine(“Enter your name:”);
string name = Console.ReadLine();
Console.WriteLine(“Hello, ” + name + “!”);
// Output:
// Enter your name:
// John
// Hello, John!
- Formatted Output:
- The Console.WriteLine() and Console.Write() methods support formatting options using composite formatting or format specifiers.
- Composite formatting uses placeholders ({0}, {1}, etc.) in the output string and corresponding arguments.
- Format specifiers (e.g., {0:N2}, {0:D4}) define specific formatting for numeric, date/time, and other types.
Example:
int age = 30;
double salary = 2500.50;
Console.WriteLine(“Age: {0}, Salary: {1:C}”, age, salary);
// Output:
// Age: 30, Salary: $2,500.50
- File Input and Output:
- The System.IO namespace provides classes for reading from and writing to files.
- The StreamReader class is used to read text from a file.
- The StreamWriter class is used to write text to a file.
Example:
using (StreamWriter writer = new StreamWriter(“output.txt”))
{
writer.WriteLine(“Hello, File Output!”);
}
using (StreamReader reader = new StreamReader(“input.txt”))
{
string line = reader.ReadLine();
Console.WriteLine(“File Input: ” + line);
}
- String Input and Output:
- The string class provides methods for formatting and manipulating strings.
- Format() is used for string formatting similar to Console.WriteLine().
- Join() concatenates an array of strings into a single string using a delimiter.
Example:
string name = “John”;
int age = 30;
string formattedString = string.Format(“My name is {0} and I am {1} years old.”, name, age);
Console.WriteLine(formattedString);
string[] fruits = { “Apple”, “Banana”, “Orange” };
string joinedString = string.Join(“, “, fruits);
Console.WriteLine(“Fruits: ” + joinedString);
// Output:
// My name is John and I am 30 years old.
// Fruits: Apple, Banana, Orange
These are the fundamental techniques for handling input and output in C#. By utilizing these methods and classes, you can interact with users, process external data, and display information effectively. Additionally, C# offers various libraries and APIs for advanced input/output operations, such as working with databases, network communication, and graphical user interfaces.