Represent Int64 as a Octal string in C#

To represent Int64 as an octal string in C#, use the Convert.ToString() method and set the base as the second parameter to 8 for octal conversion.

Int64 represents a 64-bit signed integer that can store values from -9,223,372,036,854,775,808 to 9,223,372,036,854,775,807.

Syntax

Following is the syntax for converting Int64 to octal string −

Convert.ToString(longValue, 8)

Parameters

• longValue − The Int64 value to convert

• 8 − The base for octal number system

Return Value

Returns a string representation of the Int64 value in octal format.

Example

using System;

class Demo {
    static void Main() {
        long val = 986766;
        Console.WriteLine("Long: " + val);
        Console.WriteLine("Octal String: " + Convert.ToString(val, 8));
    }
}

The output of the above code is −

Long: 986766
Octal String: 3607216

Using Multiple Int64 Values

Example

using System;

class Program {
    static void Main() {
        long[] values = { 64, 255, 1024, 8192, 986766 };
        
        Console.WriteLine("Decimal\t\tOctal");
        Console.WriteLine("-------\t\t-----");
        
        foreach (long value in values) {
            string octalString = Convert.ToString(value, 8);
            Console.WriteLine($"{value}\t\t{octalString}");
        }
    }
}

The output of the above code is −

Decimal		Octal
-------		-----
64		100
255		377
1024		2000
8192		20000
986766		3607216

Converting Negative Int64 Values

Example

using System;

class Program {
    static void Main() {
        long negativeValue = -986766;
        long positiveValue = 986766;
        
        Console.WriteLine("Positive: " + positiveValue + " -> Octal: " + Convert.ToString(positiveValue, 8));
        Console.WriteLine("Negative: " + negativeValue + " -> Octal: " + Convert.ToString(negativeValue, 8));
    }
}

The output of the above code is −

Positive: 986766 -> Octal: 3607216
Negative: -986766 -> Octal: 1777777777777777774170562

Conclusion

The Convert.ToString() method with base 8 efficiently converts Int64 values to their octal string representation. For negative numbers, the method returns the two's complement representation in octal format, which appears as a long string of leading 7s.