Type Casting in C#

Type casting means converting a variable of one data type into another, ensuring compatibility when assigning data between different types.

For Example:

using System;
class Program
{
    static void Main()
    {
        int num = 10;

        // int is converted to double (implicit type casting)
        double d = num;

        Console.WriteLine(d);

    }
}

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Type Casting can be divided into two parts:

• Implicit Type Conversion (Type Safe)
• Explicit Type Conversion (Manual Conversion)

1. Implicit Type Casting

Implicit type casting (type-safe casting) is the process in which the C# compiler automatically converts a smaller (compatible) data type into a larger data type (e.g., int to double) without any data loss. It is performed automatically by the compiler.

In C#, numeric types support implicit conversions among themselves, but not to char or bool. Also, char and bool are incompatible. The compiler ensures type compatibility before conversion.

using System;

class Program
{
    static void Main()
    {
        int x = 10;
        double d = x;  
        // implicit casting

        Console.WriteLine(d);
    }
}

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Invalid Implicit Conversion

int x = 10;
double d = 9.5;

// Error
x = d;

Error: Cannot implicitly convert double to int.

2. Explicit Type Casting

Explicit type casting is done manually using a cast operator. It is required when converting a larger data type into a smaller one and may cause data loss. Let's take a look at an example:

Example: Using Explicit Conversion to convert double into int.

using System;

class Program
{
    static void Main()
    {
        double d = 9.8;
        
        // explicit casting
        int x = (int)d;  

        Console.WriteLine(x);
    }
}

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This solves the limitation of implicit casting by using explicit casting. Additionally, we can use built-in methods for more flexible type conversions.

Type Conversion Methods

There are some built in methods defined for type conversions mentioned below:

Example: Typecasting using built-in methods

using System;

namespace Casting {
class Geeks {

    public static void Main(String[] args)
    {
        int i = 12;
        double d = 765.12;
        float f = 56.123F;

        // Using Built- In Type Conversion Methods & Displaying Result
        Console.WriteLine(Convert.ToString(f));
        Console.WriteLine(Convert.ToInt32(d));
        Console.WriteLine(Convert.ToUInt32(f));
        Console.WriteLine(Convert.ToDouble(i));
        Console.WriteLine("GeeksforGeeks");
    }
}
}