Converting characters to integers in Java

Question

Can someone please explain to me what is going on here   char c        int i    int c  System out println  i      i     ch      Character getNumericValue c      This prints i  43 ch -1  Does that mean I have to rely on primitive conversions to convert char to int  So how can I convert a Character to Integer   Edit  Yes I know Character getNumericValue returns -1 if it is not a numeric value and that makes sense to me  The question is  why does doing primitive conversions return 43   Edit2  43 is the ASCII for    but I would expect the cast to not succeed just like getNumericValue did not succeed  Otherwise that means there are two semantic equivalent ways to perform the same operation but with different results

User · Answer

From the Javadoc for Character getNumericValue      If the character does not have a numeric value  then -1 is returned    If the character has a numeric value that cannot be represented as a   nonnegative integer  for example  a fractional value   then -2 is   returned    The character   does not have a numeric value  so you re getting -1   Update   The reason that primitive conversion is giving you 43 is that the the character     is encoded as the integer 43

User · Answer

Try any one of the below  These should work   int a   Character getNumericValue  3    int a   Integer parseInt String valueOf  3

User · Answer

public class IntergerParser    public static void main String   args   String number     123123   System out println parseInt number       private static int parseInt String number       char   numChar   number toCharArray        int intValue   0      int decimal   1      for int index   numChar length   index  gt  0   index --           if index    1                if numChar index - 1      -                    return intValue   -1                else if numChar index - 1                           return intValue                                  intValue   intValue      int numChar index-1  - 48     decimal            System out println  int numChar index-1  - 48         decimal            decimal   decimal   10            return intValue

User · Answer

Character getNumericValue c    The java lang Character getNumericValue char ch  returns the int value that the specified Unicode character represents  For example  the character   u216C   the roman numeral fifty  will return an int with a value of 50   The letters A-Z in their uppercase    u0041  through   u005A    lowercase    u0061  through   u007A    and full width variant    uFF21  through   uFF3A  and   uFF41  through   uFF5A   forms have numeric values from 10 through 35  This is independent of the Unicode specification  which does not assign numeric values to these char values      This method returns the numeric value of the character  as a   nonnegative int value        -2 if the character has a numeric value that is not a nonnegative integer        -1 if the character has no numeric value    And here is the link

User · Answer

As the documentation clearly states  Character getNumericValue   returns the character s value as a digit  It returns -1 if the character is not a digit   If you want to get the numeric Unicode code point of a boxed Character object  you ll need to unbox it first   int value    int c charValue

User · Answer

43 is the dec ascii number for the     symbol   That explains why you get a 43 back  http   en wikipedia org wiki ASCII

[java] Converting characters to integers in Java

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