Octal is a number system where a number is represented in powers of 8. So all the integers can be represented as an octal number. Also, all the digit in an octal number is between 0 and 7. In java, we can store octal numbers by just adding 0 while initializing. They are called Octal Literals. The data type used for storing is int.Â
The method used to convert Decimal to Octal is Integer.toOctalString(int num)
Syntax:
public static String toOctalString(int num)
Parameters: The method accepts a single parameter num of integer type which is required to be converted to a string.
Return Value: The function returns a string representation of the integer argument as an unsigned integer in base 8.
Example 1
Java
import java.io.*;Â
class GFG {    public static void main(String[] args)    {        // Variable Declaration        int a;Â
        // storing normal integer value        a = 20;        System.out.println("Value of a: " + a);Â
        // storing octal integer value        // just add 0 followed octal representation        a = 024;        System.out.println("Value of a: " + a);Â
        // convert octal representation to integer        String s = "024";        int c = Integer.parseInt(s, 8);        System.out.println("Value of c: " + c);Â
        // get octal representation of a number        int b = 50;        System.out.println(            "Octal Representation of the number " + b            + " is: " + Integer.toOctalString(b));    }} |
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Value of a: 20 Value of a: 20 Value of c: 20 Octal Representation of the number 50 is: 62
The time complexity is O(1), meaning it is constant time.
The auxiliary space complexity is also O(1).Â
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Example 2: The different arithmetic operation can also be performed on this octal integer. Operation is the same as performed on the int data type.
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Java
// Arithmetic operations on Octal numbersÂ
import java.io.*;Â
class GFG {Â Â Â Â public static void main(String[] args)Â Â Â Â {Â Â Â Â Â Â Â Â int a, b;Â
        // 100        a = 0144;Â
        // 20        b = 024;Â
        System.out.println("Value of a: " + a);        System.out.println("Value of b: " + b);        System.out.println("Addition: " + (a + b));        System.out.println("Subtraction: " + (a - b));        System.out.println("Multiplication: " + (a * b));        System.out.println("Division: " + (a / b));    }} |
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Value of a: 100 Value of b: 20 Addition: 120 Subtraction: 80 Multiplication: 2000 Division: 5
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