Decimal to Octal Program in Java

Convert Decimal to Octal Program in Java

There are two way to convert decimal number into octal number, which is given below;

• Using predefined method Integer.toOctalString(int num)
• Writing our own logic for conversion

import java.util.Scanner;
class DecimalToOctal
{
  public static void main(String args[])
  {
    Scanner input = new Scanner( System.in );
    System.out.print("Enter a decimal number : ");
    int num =input.nextInt();
 
    String octalString = Integer.toOctalString(num);
    System.out.println("Method 1: Decimal to octal: " + octalString);

  }
}

Enter a decimal number : 123
Decimal to octal: 173

Code Explanation

Using predefined method toOctalString(int) Pass the decimal number to this method and it would return the equivalent octal number.

import java.util.Scanner;

class DecimalToOctal
{
  public static void main(String args[])
  {
    Scanner input = new Scanner( System.in );
    System.out.print("Enter a decimal number : ");
    int num =input.nextInt();
  
    // For storing remainder
    int rem;
 
    // For storing result
    String str=""; 
 
    // Digits in Octal number system
    char dig[]={'0','1','2','3','4','5','6','7'};
 
    while(num>0)
    {
       rem=num%8; 
       str=dig[rem]+str; 
       num=num/8;
    }
    System.out.println("Decimal to octal: "+str);
  }
}

Enter a decimal number : 123
Decimal to octal: 173

Syntax to compile and run java program

for compile -> c:/>javac DecimalToOctal.java
for run -> c:/>java DecimalToOctal