﻿ Java exercises: Convert a octal number to a binary number - w3resource # Java Exercises: Convert a octal number to a binary number

## Java Basic: Exercise-26 with Solution

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

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

Binary number: A binary number is a number expressed in the base-2 numeral system or binary numeral system. This system uses only two symbols: typically 1 (one) and 0 (zero).

Test Data:
Input any octal number: 7

Pictorial Presentation: Octal to Binary number Sample Solution:

Java Code:

``````import java.util.Scanner;

public class Exercise26 {
public static void main(String[] args)
{
Scanner in = new Scanner(System.in);
int[] octal_numvalues = {0, 1, 10, 11, 100, 101, 110, 111};
long octal_num, tempoctal_num, binary_num, place;
int rem;
System.out.print("Input any octal number: ");
octal_num = in.nextLong();
tempoctal_num = octal_num;
binary_num = 0;
place = 1;
while (tempoctal_num != 0)
{
rem = (int)(tempoctal_num % 10);
binary_num = octal_numvalues[rem] * place + binary_num;
tempoctal_num /= 10;
place *= 1000;
}
System.out.print("Equivalent binary number: " + binary_num+"\n");
}
}
```
```

Sample Output:

```Input any octal number: 7
Equivalent binary number: 111
```

Flowchart: Java Code Editor:

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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