Differences between C and C#

C is a general-purpose, high-level programming language originally developed by Dennis M. Ritchie to develop the UNIX operating system at Bell Labs. C was first implemented on the DEC PDP-11 computer in 1972.

C# is a simple, modern, general-purpose, object-oriented programming language developed by Microsoft within its .NET initiative led by Anders Hejlsberg. It was designed to combine the power of C++ with the simplicity of Visual Basic.

While both languages share the letter "C" in their names, they represent different programming paradigms and approaches. Here are the key differences between C and C#.

Comparison Table

Programming Paradigm

C follows a procedural programming approach where the program is structured as a collection of functions. C# is an object-oriented language that uses classes and objects as fundamental building blocks.

C Example (Procedural)

// C-style procedural approach in C#
using System;

class Program {
   static int Add(int a, int b) {
      return a + b;
   }
   
   static int Multiply(int a, int b) {
      return a * b;
   }
   
   static void Main(string[] args) {
      int result1 = Add(5, 3);
      int result2 = Multiply(4, 6);
      Console.WriteLine("Addition: " + result1);
      Console.WriteLine("Multiplication: " + result2);
   }
}

C# Example (Object-Oriented)

using System;

class Calculator {
   public int Add(int a, int b) {
      return a + b;
   }
   
   public int Multiply(int a, int b) {
      return a * b;
   }
}

class Program {
   static void Main(string[] args) {
      Calculator calc = new Calculator();
      int result1 = calc.Add(5, 3);
      int result2 = calc.Multiply(4, 6);
      Console.WriteLine("Addition: " + result1);
      Console.WriteLine("Multiplication: " + result2);
   }
}

The output of both examples is −

Addition: 8
Multiplication: 24

Memory Management

C requires manual memory management using functions like malloc() and free(). C# provides automatic memory management through the garbage collector, which automatically deallocates unused objects.

Example - Automatic Garbage Collection in C#

using System;

class Person {
   public string Name;
   public Person(string name) {
      Name = name;
      Console.WriteLine(name + " object created");
   }
   
   ~Person() {
      Console.WriteLine(Name + " object destroyed by GC");
   }
}

class Program {
   static void Main(string[] args) {
      Person p1 = new Person("John");
      Person p2 = new Person("Alice");
      
      p1 = null; // Object eligible for garbage collection
      p2 = null;
      
      GC.Collect(); // Force garbage collection
      GC.WaitForPendingFinalizers();
      
      Console.WriteLine("Program completed");
   }
}

The output of the above code is −

John object created
Alice object created
Alice object destroyed by GC
John object destroyed by GC
Program completed

Platform and Runtime

C programs compile to native machine code and can run on various platforms without additional runtime dependencies. C# programs compile to Intermediate Language (IL) and require the .NET runtime to execute.

Example - Platform Information in C#

using System;

class Program {
   static void Main(string[] args) {
      Console.WriteLine("Operating System: " + Environment.OSVersion);
      Console.WriteLine(".NET Version: " + Environment.Version);
      Console.WriteLine("Machine Name: " + Environment.MachineName);
      Console.WriteLine("Current Directory: " + Environment.CurrentDirectory);
   }
}

The output will vary based on your system, but might look like −

Operating System: Microsoft Windows NT 10.0.19044.0
.NET Version: 4.0.30319.42000
Machine Name: DESKTOP-ABC123
Current Directory: C:\Users\YourName\Documents

Conclusion

C is a procedural language with manual memory management ideal for system programming, while C# is an object-oriented language with automatic memory management designed for application development within the .NET ecosystem. The choice between them depends on your project requirements, target platform, and programming preferences.