Tech Jargon - Decoded

#Java #BinaryHex #Conversion

Binary to Hex Conversion

public class BinaryToHex {
    public static String binaryToHex(String binary) {
        if (binary == null || binary.isEmpty() || binary.length() % 4 != 0) {
            return "Invalid Binary Input";
        }

        StringBuilder hex = new StringBuilder();
        for (int i = 0; i < binary.length(); i += 4) {
            String nibble = binary.substring(i, i + 4);
            int decimal = Integer.parseInt(nibble, 2);
            hex.append(Integer.toHexString(decimal));
        }
        return hex.toString().toUpperCase();
    }

    public static void main(String[] args) {
        String binaryString = "1010111100001111";
        String hexString = binaryToHex(binaryString);
        System.out.println("Binary: " + binaryString);
        System.out.println("Hex: " + hexString);
    }
}

#Java #HexConversion

Hex to Decimal Conversion

public class HexToDecimal {
 public static int hexToDecimal(String hex) {
  int decimal = 0;
  for (int i = 0; i < hex.length(); i++) {
   char hexChar = hex.charAt(i);
   int digitValue = hexCharToDecimal(hexChar);
   if (digitValue == -1) {
    throw new IllegalArgumentException("Invalid hex character: " + hexChar);
   }
   decimal = decimal * 16 + digitValue;
  }
  return decimal;
 }

 public static int hexCharToDecimal(char hexChar) {
  if (hexChar >= '0' && hexChar <= '9') {
   return hexChar - '0';
  } else if (hexChar >= 'A' && hexChar <= 'F') {
   return hexChar - 'A' + 10;
  } else if (hexChar >= 'a' && hexChar <= 'f') {
   return hexChar - 'a' + 10;
  } else {
   return -1;
  }
 }

 public static void main(String[] args) {
  String hexValue = "1A";
  int decimalValue = hexToDecimal(hexValue);
  System.out.println("Hexadecimal " + hexValue + " = Decimal " + decimalValue);
 }
}

#Java #OctalToDecimal #CodingInterview

Octal to Decimal Conversion

public class OctalToDecimal {
 public static int octalToDecimal(String octal) {
 int decimal = 0;
 int power = 0;
 for (int i = octal.length() - 1; i >= 0; i--) {
 int digit = octal.charAt(i) - '0';
 decimal += digit * Math.pow(8, power);
 power++;
 }
 return decimal;
 }

 public static void main(String[] args) {
 String octalNumber = "17";
 int decimalNumber = octalToDecimal(octalNumber);
 System.out.println(octalNumber + " in octal is " + decimalNumber + " in decimal.");
 }
}

#Java #BinaryConversion

Binary to Decimal Conversion

public class BinaryToDecimal {
    public static int binaryToDecimal(String binary) {
        int decimal = 0;
        int power = 0;
        for (int i = binary.length() - 1; i >= 0; i--) {
            int digit = binary.charAt(i) - '0';
            if (digit < 0 || digit > 1) {
                throw new IllegalArgumentException("Invalid binary string: " + binary);
            }
            decimal += digit * Math.pow(2, power);
            power++;
        }
        return decimal;
    }

    public static void main(String[] args) {
        String binaryString = "101101";
        int decimalValue = binaryToDecimal(binaryString);
        System.out.println("Binary " + binaryString + " = Decimal " + decimalValue);
    }
}

#Java #NumberConversion #InterviewPrep

Decimal to Binary, Octal, Hexadecimal Conversion in Java

public class DecimalConverter {
    public static void main(String[] args) {
        int decimal = 255;

        String binary = Integer.toBinaryString(decimal);
        String octal = Integer.toOctalString(decimal);
        String hexadecimal = Integer.toHexString(decimal);

        System.out.println("Decimal: " + decimal);
        System.out.println("Binary: " + binary);
        System.out.println("Octal: " + octal);
        System.out.println("Hexadecimal: " + hexadecimal);
    }
}

#Java #Algorithm

Find Digital Root

public class DigitalRoot {

    public static int digitalRoot(int n) {
        while (n >= 10) {
            int sum = 0;
            while (n > 0) {
                sum += n % 10;
                n /= 10;
            }
            n = sum;
        }
        return n;
    }

    public static void main(String[] args) {
        System.out.println(digitalRoot(16));
        System.out.println(digitalRoot(942));
        System.out.println(digitalRoot(493193));
    }
}

#Java #BigInteger

Factorial using BigInteger

import java.math.BigInteger;

public class FactorialBigInteger {

    public static BigInteger factorial(int n) {
        BigInteger result = BigInteger.ONE;
        for (int i = 2; i <= n; i++) {
            result = result.multiply(BigInteger.valueOf(i));
        }
        return result;
    }

    public static void main(String[] args) {
        int number = 50;
        BigInteger fact = factorial(number);
        System.out.println("Factorial of " + number + " is: " + fact);
    }
}

#Java #Recursion #Algorithm

Sum of Digits (Recursive & Iterative)

public class SumOfDigits {

    public static int sumDigitsIterative(int n) {
        int sum = 0;
        while (n > 0) {
            sum += n % 10;
            n /= 10;
        }
        return sum;
    }

    public static int sumDigitsRecursive(int n) {
        if (n == 0) {
            return 0;
        }
        return (n % 10) + sumDigitsRecursive(n / 10);
    }

    public static void main(String[] args) {
        int number = 12345;
        System.out.println("Iterative Sum: " + sumDigitsIterative(number));
        System.out.println("Recursive Sum: " + sumDigitsRecursive(number));
    }
}

#Java #Algorithm #Math

Sum of First N Even/Odd Numbers

public class SumEvenOdd {
    public static int sumOfFirstNEven(int n) {
        return n * (n + 1);
    }

    public static int sumOfFirstNOdd(int n) {
        return n * n;
    }

    public static void main(String[] args) {
        int n = 5;
        System.out.println("Sum of first " + n + " even numbers: " + sumOfFirstNEven(n));
        System.out.println("Sum of first " + n + " odd numbers: " + sumOfFirstNOdd(n));
    }
}

#Java #Algorithms

Sum of First N Natural Numbers

public class SumOfN {
    public static int sum(int n) {
        if (n <= 0) {
            return 0;
        }
        return n * (n + 1) / 2;
    }

    public static void main(String[] args) {
        int number = 5;
        int result = sum(number);
        System.out.println("Sum of first " + number + " natural numbers: " + result);
    }
}