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Java Exercises: Convert a octal number to a decimal number

Java Basic: Exercise-25 with Solution

Write a Java program to convert a octal number to a decimal number.

Octal number: The octal numeral system is the base-8 number system, and uses the digits 0 to 7.

Decimal number: The decimal numeral system is the standard system for denoting integer and non-integer numbers. It is also called base-ten positional numeral system.

Test Data:
Input any octal number: 10

Pictorial Presentation: Octal to Decimal number

Java: Convert a octal number to a decimal number

Sample Solution:

Java Code:

import java.util.Scanner;

public class Exercise25 {
 
public static void main(String[] args) 
   {
     Scanner in = new Scanner(System.in);
     long octal_num, decimal_num = 0;
     int i = 0;
     System.out.print("Input any octal number: ");
    octal_num = in.nextLong();
    while (octal_num != 0) 
     {
      decimal_num = (long)(decimal_num + (octal_num % 10) * Math.pow(8, i++));
      octal_num = octal_num / 10;
     }
    System.out.print("Equivalent decimal number: " + decimal_num+"\n");
   }
}

Sample Output: 

Input any octal number: 10                                                                                    
Equivalent decimal number: 8

Flowchart:

Flowchart: Java exercises: Convert a octal number to a decimal number

Java Code Editor:

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Previous: Write a Java program to convert a binary number to a Octal number.
Next: Write a Java program to convert a octal number to a binary number.

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Java: Tips of the Day

Try and catch:

Java is excellent at catching errors, but it can only recover gracefully if you tell it what to do. The cascading hierarchy of attempting to perform an action in Java starts with try, falls back to catch, and ends with finally. Should the try clause fail, then catch is invoked, and in the end, there's always finally to perform some sensible action regardless of the results. Here's an example:

try {
        cmd = parser.parse(opt, args); 
       
        if(cmd.hasOption("help")) {
                HelpFormatter helper = new HelpFormatter();
                helper.printHelp("Hello ", opt);
                System.exit(0);
                }
        else {
                if(cmd.hasOption("shell") || cmd.hasOption("s")) {
                String target = cmd.getOptionValue("tgt");
                } // else
        } // fi
} catch (ParseException err) {
        System.out.println(err);
        System.exit(1);
        } //catch
        finally {
                new Hello().helloWorld(opt);
        } //finally
} //try

It's a robust system that attempts to avoid irrecoverable errors or, at least, to provide you with the option to give useful feedback to the user. Use it often, and your users will thank you!

Ref: https://red.ht/3EZc9OC