Example: Decimal To Octal Conversion

DecimalToOctalDemo.java

/**
 * Example: Conversion from decimal to octal
 * Reference: https://www.rapidtables.com/convert/number/decimal-to-binary.html, https://byjus.com/maths/convert-decimal-to-octal/
 * Sample Data:
 * 11 - 13
 * 21 - 25
 * 57 - 71
 * 17 - 21
 *
 * Example 1: Convert (127)10 to Octal.
 * Solution: Divide 127 by 8
 * 127 ÷ 8= 15(Quotient) and (7)Remainder
 * Divide 15 by 8 again.
 * 15 ÷ 8 = 1(Quotient) and (7) Remainder
 * Divide 1 by 8, we get;
 * 1 ÷ 8 = 0(Quotient) and (1) Remainder
 * Since the quotient is zero now, no more division can be done. So by taking the remainders in reverse order, we get the equivalent octal number.
 * Hence, (127)10 = (177)8
 **/
public class DecimalToOctalDemo {
    public static void main(String[] args) {
        int num=127, rem;
        StringBuilder ans= new StringBuilder();
        while(num>0){
            rem = num%8;
            num=num/8;
            ans.append(rem);
        }
        ans.reverse();
        System.out.println(ans);
    }
}