C# Basics

• Declarations:

using System;

class Program { static void Main() { // Variable declaration and assignment

    int age = 25;
    string name = "John Doe";
    float temperature = 98.6f;
    bool isStudent = true;

    // Displaying the values of the variables

    Console.WriteLine("Name: " + name);
    Console.WriteLine("Age: " + age);
    Console.WriteLine("Temperature: " + temperature);
    Console.WriteLine("Is Student: " + isStudent);

    // Modifying variable values
    age = 26;
    temperature = 99.2f;
    isStudent = false;

    Console.WriteLine("\nModified values:");

    Console.WriteLine("Age: " + age);
    Console.WriteLine("Temperature: " + temperature);
    Console.WriteLine("Is Student: " + isStudent);
}

}  

• Read and write: using System;

class Program { static void Main() { Console.WriteLine("What is your name?"); string name = Console.ReadLine();

    Console.WriteLine("How old are you?");
    int age = Convert.ToInt32(Console.ReadLine());

    Console.WriteLine("What is your favorite color?");
    string color = Console.ReadLine();

    Console.WriteLine("\nThank you for providing the following information:");
    Console.WriteLine("Name: " + name);
    Console.WriteLine("Age: " + age);
    Console.WriteLine("Favorite Color: " + color);
}

}  

• Selection statements: If statement: if (condition) { // Code to execute if the condition is true } int num = 10; if (num > 0) { Console.WriteLine("The number is positive."); }

If else statement: if (condition) { // Code to execute if the condition is true } else { // Code to execute if the condition is false }

int num = 10; if (num > 0) { Console.WriteLine("The number is positive."); } else { Console.WriteLine("The number is not positive."); }

• Switch statement:

switch (variable) { case value1: // Code to execute if variable matches value1 break; case value2: // Code to execute if variable matches value2 break; // More case statements... default: // Code to execute if no case matches break; }

char grade = 'B'; switch (grade) { case 'A': Console.WriteLine("Excellent!"); break; case 'B': Console.WriteLine("Good job!"); break; case 'C': Console.WriteLine("Keep going!"); break; default: Console.WriteLine("Try again next time!"); break; }