Decimal to Hexadecimal Converter in Java

Question

I have a homework assignment where I need to do three-way conversion between decimal  binary and hexadecimal  The function I need help with is converting a decimal into a hexadecimal  I have nearly no understanding of hexadecimal  nonetheless how to convert a decimal into hex  I need a function that takes in an int dec and returns a String hex  Unfortunately I don t have any draft of this function  I m completely lost  All I have is this     public static String decToHex int dec          String hex             return hex        Also I can t use those premade functions like Integer toHexString   or anything  I need to actually make the algorithm or I wouldn t have learned anything

User · Answer

I need a function that takes in an int dec and returns a String hex.

I found a more elegant solution from http://introcs.cs.princeton.edu/java/31datatype/Hex2Decimal.java.html . I changed a bit from the original ( see the edit )

// precondition:  d is a nonnegative integer
public static String decimal2hex(int d) {
    String digits = "0123456789ABCDEF";
    if (d <= 0) return "0";
    int base = 16;   // flexible to change in any base under 16
    String hex = "";
    while (d > 0) {
        int digit = d % base;              // rightmost digit
        hex = digits.charAt(digit) + hex;  // string concatenation
        d = d / base;
    }
    return hex;
}

Disclaimer: I ask this question in my coding interview. I hope this solution doesn't get too popular :)

Edit June 17 2016 : I added the base variable to give the flexibility to change into any base : binary, octal, base of 7 ...
According to the comments, this solution is the most elegant so I removed the implementation of Integer.toHexString() .

Edit September 4 2015 : I found a more elegant solution http://introcs.cs.princeton.edu/java/31datatype/Hex2Decimal.java.html

User · Answer

Here is the code for any number    import java math BigInteger   public class Testing            param args     static String arr      0   1   2   3   4   5   6   7   8   9   A   B   C   D   E   F     public static void main String   args        String value    214       System out println value           getHex value        public static String getHex String value        String output          try           Integer parseInt value           Integer number   new Integer value           while number  gt   16               output   arr number 16    output              number   number 16                    output   arr number  output         catch  Exception e            BigInteger number   null          try              number   new BigInteger value            catch  Exception e1                return  Not a valid numebr                     BigInteger hex   new BigInteger  16            BigInteger   val                while number compareTo hex     1    number compareTo hex     0               val   number divideAndRemainder hex               output   arr val 1  intValue      output              number   val 0                     output   arr number intValue      output             return output

User · Answer

Another possible solution   public String DecToHex int dec     char   hexDigits     0    1    2    3    4    5    6    7    8    9                  A    B    C    D    E    F      String hex         while  dec    0          int rem   dec   16        hex   hexDigits rem    hex        dec   dec   16        return hex

User · Answer

A better solution to convert Decimal To HexaDecimal and this one is less complex  import java util Scanner  public class DecimalToHexa       public static void main String ar                  Scanner sc new Scanner System in           System out println  Enter a Decimal number              int n sc nextInt            if n lt 0                        System out println  Enter a positive integer                return                    int i 0 d 0          String hx    h             while n gt 0                        d n 16  enter code here              n  16              if d  10 h  A               else if d  11 h  B               else if d  12 h  C               else if d  13 h  D               else if d  14 h  E               else if d  15 h  F               else h    d                          hx    h hx                    System out println  Equivalent HEXA    hx

User · Answer

Check out the code below for decimal to hexadecimal conversion   import java util Scanner   public class DecimalToHexadecimal      public static void main String   args             int temp  decimalNumber        String hexaDecimal             char hexa       0   1   2   3   4   5   6   7   8   9   A   B   C   D   E   F           Scanner sc   new Scanner System in         System out print  Please enter decimal number             decimalNumber   sc nextInt           while decimalNumber  gt  0                   temp   decimalNumber   16           hexaDecimal   hexa temp    hexaDecimal           decimalNumber   decimalNumber   16                 System out print  The hexadecimal value of     decimalNumber     is       hexaDecimal               sc close             You can learn more on different ways to convert decimal to hexadecimal in the following link    java convert decimal to hexadecimal

User · Answer

I will use   Long a   Long parseLong cadenaFinal  16      since there is some hex that can be larguer than intenger and it will throw an exception

User · Answer

Consider dec2m method below for conversion from dec to hex  oct or bin   Sample output is  28 dec    11100 bin  28 dec    34 oct  28 dec    1C hex  public class Conversion       public static void main String   argv            int x   28                               sample number         if  argv length  gt  0              x   Integer parseInt argv 0          number from command line          System out printf   d dec     s bin n   i  dec2m x  2            System out printf   d dec     s oct n   i  dec2m x  8            System out printf   d dec     s hex n   i  dec2m x  16               static String dec2m int N  int m            String s               for  int n   N  n  gt  0  n    m                int r   n   m              s   r  lt  10   r   s    char    A  - 10   r    s                    return s

User · Answer

The easiest way to do this is   String hexadecimalString   String format   x   integerValue

User · Answer

Simple     public static String decToHex int dec              return Integer toHexString dec         As mentioned here  Java Convert integer to hex integer

User · Answer

Here s mine  public static String dec2Hex int num        String hex            while  num    0                if  num   16  lt  10              hex   Integer toString num   16    hex          else             hex    char   num   16  55    hex          num   num   16             return hex

User · Answer

One possible solution   import java lang StringBuilder   class Test     private static final int sizeOfIntInHalfBytes   8    private static final int numberOfBitsInAHalfByte   4    private static final int halfByte   0x0F    private static final char   hexDigits           0    1    2    3    4    5    6    7         8    9    A    B    C    D    E    F          public static String decToHex int dec        StringBuilder hexBuilder   new StringBuilder sizeOfIntInHalfBytes       hexBuilder setLength sizeOfIntInHalfBytes       for  int i   sizeOfIntInHalfBytes - 1  i  gt   0  --i              int j   dec  amp  halfByte        hexBuilder setCharAt i  hexDigits j          dec  gt  gt   numberOfBitsInAHalfByte            return hexBuilder toString            public static void main String   args         int dec   305445566       String hex   decToHex dec        System out println hex                  Output   1234BABE   Anyway  there is a library method for this    String hex   Integer toHexString dec

User · Answer

Code to convert DECIMAL -to-  BINARY  OCTAL  HEXADECIMAL  public class ConvertBase10ToBaseX       enum Base                          Integer is represented in 32 bit in 32 64 bit machine             There we can split this integer no of bits into multiples of 1 2 4 8 16 bits                     BASE2 1 1 32   BASE4 3 2 16   BASE8 7 3 11    OCTAL      BASE10 3 2              BASE16 15  4  8                      public String getFormattedValue int val                   switch val                    case 10                      return  A                   case 11                      return  B                   case 12                      return  C                   case 13                      return  D                   case 14                      return  E                   case 15                      return  F                   default                      return      val                                                BASE32 31 5 1     BASE256 255  8  4     BASE512 511 9     Base65536 65535  16  2            private int LEVEL 0 MASK          private int LEVEL 1 ROTATION          private int MAX ROTATION           Base int levelZeroMask  int levelOneRotation  int maxPossibleRotation                this LEVEL 0 MASK   levelZeroMask              this LEVEL 1 ROTATION   levelOneRotation              this MAX ROTATION   maxPossibleRotation                     int getLevelZeroMask                return LEVEL 0 MASK                    int getLevelOneRotation                return LEVEL 1 ROTATION                    int getMaxRotation                return MAX ROTATION                    String getFormattedValue int val               return      val                       public void getBaseXValueOn Base base  int on            forwardPrint base  on              private void forwardPrint Base base  int on             int rotation   base getLevelOneRotation            int mask   base getLevelZeroMask            int maxRotation   base getMaxRotation            boolean valueFound   false           for int level   maxRotation  level  gt   2  level--                int rotation1    level-1    rotation              int mask1   mask  lt  lt  rotation1               if  on  amp  mask1   gt  0                     valueFound   true                            if valueFound              System out print base getFormattedValue  on  amp  mask1   gt  gt  gt  rotation1                      System out println base getFormattedValue  on  amp  mask                public int getBaseXValueOnAtLevel Base base  int on  int level            if level  gt  base getMaxRotation      level  lt  1                return 0    INVALID Input                   int rotation   base getLevelOneRotation            int mask   base getLevelZeroMask             if level  gt  1                rotation    level-1    rotation              mask   mask  lt  lt  rotation            else               rotation   0                      return  on  amp  mask   gt  gt  gt  rotation             public static void main String   args            ConvertBase10ToBaseX obj   new ConvertBase10ToBaseX             obj getBaseXValueOn Base BASE16 12456            obj getBaseXValueOn Base BASE16 300            obj getBaseXValueOn Base BASE16 7            obj getBaseXValueOn Base BASE16 7            obj getBaseXValueOn Base BASE2 12456           obj getBaseXValueOn Base BASE8 12456           obj getBaseXValueOn Base BASE2 8           obj getBaseXValueOn Base BASE2 9           obj getBaseXValueOn Base BASE2 10           obj getBaseXValueOn Base BASE2 11           obj getBaseXValueOn Base BASE2 12           obj getBaseXValueOn Base BASE2 13           obj getBaseXValueOn Base BASE2 14           obj getBaseXValueOn Base BASE2 15           obj getBaseXValueOn Base BASE2 16           obj getBaseXValueOn Base BASE2 17             System out println obj getBaseXValueOnAtLevel Base BASE2  4  1             System out println obj getBaseXValueOnAtLevel Base BASE2  4  2             System out println obj getBaseXValueOnAtLevel Base BASE2  4  3             System out println obj getBaseXValueOnAtLevel Base BASE2  4  4              System out println obj getBaseXValueOnAtLevel Base BASE16 15  1             System out println obj getBaseXValueOnAtLevel Base BASE16 30  2             System out println obj getBaseXValueOnAtLevel Base BASE16 7  1             System out println obj getBaseXValueOnAtLevel Base BASE16 7  2              System out println obj getBaseXValueOnAtLevel Base BASE256  511  1             System out println obj getBaseXValueOnAtLevel Base BASE256  511  2             System out println obj getBaseXValueOnAtLevel Base BASE256  512  1            System out println obj getBaseXValueOnAtLevel Base BASE256  512  2             System out println obj getBaseXValueOnAtLevel Base BASE256  513  2

User · Answer

The following converts decimal to Hexa Decimal with Time Complexity   O n  Linear Time with out any java inbuilt function  private static String decimalToHexaDecimal int N        char hexaDecimals        0    1    2    3    4    5    6    7    8    9    A    B    C    D    E    F         StringBuilder builder   new StringBuilder        int base  16      while  N    0            int reminder   N   base          builder append hexaDecimals reminder            N   N   base             return builder reverse   toString

[java] Decimal to Hexadecimal Converter in Java

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