ConvertBinaryToOctal()

Step 1

Start by defining a Java function that takes in a binary number as a string parameter.

public static int binaryToOctal(String binary){}

Step 2

Inside the function, the first task will be to convert binary into a decimal number. We will do this by parsing the binary string into an integer using radix 2.

public static int binaryToOctal(String binary){
    int decimal = Integer.parseInt(binary, 2);
}

Step 3

The next task is to convert the decimal number into an octal. To do this, declare a variable octal and a counter variable, then use a while loop to extract each digit.

public static int binaryToOctal(String binary){
    int decimal = Integer.parseInt(binary, 2);

    int octal = 0, counter = 0;

    while(decimal > 0){
        int rem = decimal % 8;
        decimal = decimal / 8;
        octal += rem * Math.pow(10, counter);
        counter++;
    }
    return octal;
}

Step 4

The while loop uses the modulus operator to get the remainder of dividing the decimal number by 8 and the division operator to update the decimal number. The octal number is then updated by adding the remainder multiplied by 10 raised to the power of the counter. The counter is then incremented.

Step 5

Finally, the method returns the octal number that was calculated, which represents the binary number that was passed in as an octal number.

public static int binaryToOctal(String binary){
    int decimal = Integer.parseInt(binary, 2);
    int octal = 0, counter = 0;
    while(decimal > 0){
        int rem = decimal % 8;
        decimal = decimal / 8;
        octal += rem * Math.pow(10, counter);
        counter++;
    }
    return octal;
}

Conclusion

So, by following these steps, we are able to create a function that is able to accept a binary number as input (in string form) and produce its correlating octal value. These steps have been encapsulated within a function that is able to be used generically for any such conversion.

Full Code:

public static int binaryToOctal(String binary){
    int decimal = Integer.parseInt(binary, 2);
    int octal = 0, counter = 0;
    while(decimal > 0){
        int rem = decimal % 8;
        decimal = decimal / 8;
        octal += rem * Math.pow(10, counter);
        counter++;
    }
    return octal;
}