Question

Description

For this program, you are going to convert decimal (integer) numbers into their octal number (integer) equivalents. Make sure that you create a new Project and Java class file for this assignment. Your Repl.It file should be named “Main.java”. You can read about octal-to-decimal number conversions from wikepedia or another website

Instructions

• The input to the program will be a single non-negative integer number. If the number is less than or equal to 2097151, convert the number to its octal equivalent.

  • If the number is larger than 2097151, output the phrase “UNABLE TO CONVERT” and quit the program.

• The output of your program will always be a 7-digit octal number with no spaces between any of the digits. Some of the leading digits maybe 0. It may help to think that you may output each digit of the octal number individually as you calculate it, as long as you don't put spaces or newlines in your output between each digit.

• Use a while loop to solve the problem.
• DO NOT USE Strings.
• Here are a few examples of decimal numbers and their octal number equivalents:
  octal conversion examples.png

Goals

• Experience with the while loop.
• Experience with if/else.

Sample Runs

Sample Program Run
Please enter a number between 0 and 2097151 to convert: 160000
Your integer number 160000 is 0470400 in octal.

Sample Program Run
Please enter a number between 0 and 2097151 to convert: 5000000
UNABLE TO CONVERT

Answer 1

// Main.java : Java program to convert decimal number to octal
public class Main {

   public static void main(String[] args) {
      
       int inputNum, convertedNum;
       Scanner scan = new Scanner(System.in);
       // Input of integer number in decimal
       System.out.print("Please enter a number between 0 and 2097151 to convert: ");
       inputNum = scan.nextInt();
       // validate the number
       if(inputNum < 0 || inputNum > 2097151)
           System.out.println("UNABLE TO CONVERT");
       else
       {
           int weight=0; // weight of the digit, used for converting to octal
           convertedNum = 0; // variable to store the number in octal
           int temp = inputNum;
           int digit;
           // loop that continues till we convert the entire number to octal
           while(temp > 0)
           {
               digit = (temp%8); // get the remainder when the number is divided by 8
               // multiply the digit with its weight and add it to convertedNum
               convertedNum += digit*Math.pow(10, weight);
               temp = temp/8; // remove the last digit from the number
               weight++; // increment the weight
           }
           // display the integer in octal
           System.out.printf("Your integer number 160000 is %07d in octal",convertedNum);
       }
      
       scan.close();

}
}
//end of Main.java

Output: