The Duck Pond Splash Down

Day 1: Basics of C# – Part 1

Objective: Get familiar with the basic syntax and concepts of C#.

Topics Covered:

1. Introduction to C# and .NET framework
2. Basic structure of a C# program
3. Data types and variables
4. Operators (arithmetic, relational, logical)

Topic 1: Introduction to C# and .NET Framework

C# is a modern, object-oriented programming language developed by Microsoft. It’s part of the .NET framework, which provides a large library and runtime for building various types of applications.

Topic 2: Basic Structure of a C# Program

Here is a simple C# program that prints “Hello, World!” to the console:

using System;

namespace HelloWorld
{
    class Program
    {
        static void Main(string[] args)
        {
            Console.WriteLine("Hello, World!");
        }
    }
}

Explanation:

• using System; – Imports the System namespace, which contains fundamental classes for base functionalities.
• namespace HelloWorld – Declares a namespace named HelloWorld to organize code.
• class Program – Defines a class named Program.
• static void Main(string[] args) – The entry point of the program. The Main method is where the program starts executing.
• Console.WriteLine("Hello, World!"); – Prints “Hello, World!” to the console.

Topic 3: Data Types and Variables

Variables are used to store data in a program. Each variable in C# has a type, which determines what kind of data it can store.

Example:

using System;

namespace VariablesDemo
{
    class Program
    {
        static void Main(string[] args)
        {
            int age = 25;               // Integer
            double height = 5.9;        // Floating point number
            char initial = 'C';         // Character
            string name = "Carolyn";    // String
            bool isStudent = true;      // Boolean

            Console.WriteLine("Name: " + name);
            Console.WriteLine("Age: " + age);
            Console.WriteLine("Height: " + height);
            Console.WriteLine("Initial: " + initial);
            Console.WriteLine("Is Student: " + isStudent);
        }
    }
}

Explanation:

• int age = 25; – Declares an integer variable named age and initializes it to 25.
• double height = 5.9; – Declares a double variable named height and initializes it to 5.9.
• char initial = 'C'; – Declares a char variable named initial and initializes it to ‘C’.
• string name = "Carolyn"; – Declares a string variable named name and initializes it to “Carolyn”.
• bool isStudent = true; – Declares a boolean variable named isStudent and initializes it to true.

Topic 4: Operators

Operators are symbols that perform operations on variables and values. C# has several types of operators.

Arithmetic Operators:

using System;

namespace ArithmeticOperators
{
    class Program
    {
        static void Main(string[] args)
        {
            int a = 10;
            int b = 5;

            Console.WriteLine("Addition: " + (a + b));
            Console.WriteLine("Subtraction: " + (a - b));
            Console.WriteLine("Multiplication: " + (a * b));
            Console.WriteLine("Division: " + (a / b));
            Console.WriteLine("Modulus: " + (a % b));
        }
    }
}

Relational Operators:

using System;

namespace RelationalOperators
{
    class Program
    {
        static void Main(string[] args)
        {
            int x = 10;
            int y = 5;

            Console.WriteLine("x == y: " + (x == y));
            Console.WriteLine("x != y: " + (x != y));
            Console.WriteLine("x > y: " + (x > y));
            Console.WriteLine("x < y: " + (x < y));
            Console.WriteLine("x >= y: " + (x >= y));
            Console.WriteLine("x <= y: " + (x <= y));
        }
    }
}

Logical Operators:

using System;

namespace LogicalOperators
{
    class Program
    {
        static void Main(string[] args)
        {
            bool a = true;
            bool b = false;

            Console.WriteLine("a && b: " + (a && b)); // Logical AND
            Console.WriteLine("a || b: " + (a || b)); // Logical OR
            Console.WriteLine("!a: " + (!a));         // Logical NOT
        }
    }
}

Example Exercise

Write a program that takes two numbers as input from the user and prints their sum, difference, product, and quotient.

using System;

namespace SimpleCalculator
{
    class Program
    {
        static void Main(string[] args)
        {
            Console.Write("Enter the first number: ");
            int num1 = Convert.ToInt32(Console.ReadLine());

            Console.Write("Enter the second number: ");
            int num2 = Convert.ToInt32(Console.ReadLine());

            int sum = num1 + num2;
            int difference = num1 - num2;
            int product = num1 * num2;
            double quotient = (double)num1 / num2;

            Console.WriteLine("Sum: " + sum);
            Console.WriteLine("Difference: " + difference);
            Console.WriteLine("Product: " + product);
            Console.WriteLine("Quotient: " + quotient);
        }
    }
}

Explanation:

• Console.ReadLine() reads a line of input from the console.
• Convert.ToInt32() converts the input string to an integer.
• The program performs arithmetic operations and prints the results.

This concludes the Day 1 topics. For Day 2 click here