Convert Hexadecimal to Octal in Java()

Step 1: Understanding Hexadecimal and Octal Numbers

Hexadecimal is a base 16 number system. It uses the digits from 0 to 9 and the letters from A to F to represent decimal values 10 to 15. On the other hand, octal is a base 8 number system. It uses the digits from 0 to 7. So, to convert from hexadecimal to octal, we first need to convert from hexadecimal to binary, then from binary to octal.

 public String toBinary(String hex){
 String binary="";
    for(int i=0; i<hex.length(); i++){
        int bin = Integer.parseInt(hex.charAt(i) + "", 16);
        binary += String.format("%04d", Integer.parseInt(Integer.toBinaryString(bin)));
    }
    return binary;
}

Step 2: Converting Hexadecimal to Binary

Each hex digit is equal to a 4-digit binary number. We use a for loop to go through each character in the hexadecimal string, convert it to a decimal integer using Integer.parseInt(), and then to a binary string using Integer.toBinaryString(). We use String.format() to ensure the binary string has 4 digits.

Step 3: Converting Binary to Octal

Binary numbers are converted to octal by splitting them into groups of three, starting from the least significant digit and padding with zeros if necessary. A switch case is used to map each 3-digit binary number to its corresponding octal digit.

public String toOctal(String binary){
  String octal="";
    while(binary.length()%3 != 0){
        binary = "0" + binary; // padding with zeros
    }
    for(int i=0; i<binary.length()-2; i+=3){
        int num = Integer.parseInt(binary.substring(i,i+3),2);
        octal += Integer.toOctalString(num);
    }
    return octal;
}

Step 4: Putting It All Together

Finally, we create the convertHexToOctal() function that takes a hexadecimal string as input, converts it to binary, then converts that binary to octal, and returns the octal string.

public String convertHexToOctal(String hex){
    String binary = toBinary(hex);
    String octal = toOctal(binary);
    return octal;
}

Conclusion

Now we have a JAVA program that perfectly converts a hexadecimal number into octal.