How to convert an ASCII character into an int in C

Question

How can I convert an ASCII character into an int in C

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It is not possible with the C99 standard library  unless you manually write a map from character constants to the corresponding ASCII int value   Character constants in C like  a  are not guaranteed to be ASCII   C99 only makes some guarantees about those constants  e g  that digits be contiguous   The word ASCII only appears on the C99 N1256 standard draft in footer notes  and footer note 173  says      In an implementation that uses the seven-bit US ASCII character set  the printing characters are those   whose values lie from 0x20  space  through 0x7E  tilde   the control characters are those whose   values lie from 0  NUL  through 0x1F  US   and the character 0x7F  DEL     implying that ASCII is not the only possibility

User · Answer

I agree to Ashot and Cwan  but maybe you like to convert an ascii-cipher like  7  into an int like 7    Then I recoomend    char seven    7   int i   seven -  0       or  maybe you get a warning    int i    int   seven -  0        corrected after comments  thanks

User · Answer

Are you searching for this   int c   some ascii character    Or just converting without assignment    int some aschii character

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What about   int a as int    int  a

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A char value in C is implicitly convertible to an int  e g  char c      printf   d   c  prints the decimal ASCII value of c  and int i   c  puts the ASCII integer value of c in i  You can also explicitly convert it with  int c  If you mean something else  such as how to convert an ASCII digit to an int  that would be c -  0   which implicitly converts c to an int and then subtracts the ASCII value of  0   namely 48  in C  character constants such as  0  are of type int  not char  for historical reasons

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As everyone else told you  you can convert it directly    UNLESS you meant something like  how can I convert an ASCII Extended character to its UTF-16 or UTF-32 value   This is a TOTALLY different question  one at least as good   And one quite difficult  if I remember correctly  if you are using only  pure  C  Then you could start here  https   stackoverflow com questions 114611 what-is-the-best-unicode-library-for-c 114643 114643   for ASCII Extended I mean one of the many  extensions  to the ASCII set  The 0-127 characters of the base ASCII set are directly convertible to Unicode  while the 128-255 are not    For example ISO 8859-1 http   en wikipedia org wiki ISO 8859-1 is an 8 bit extensions to the 7 bit ASCII set  or the  quite famous  codepages 437 and 850

User · Answer

You mean the ASCII ordinal value  Try type casting like this one   int x    a

User · Answer

Use the ASCII to Integer atoi   function which accepts a string and converts it into an integer    include  lt stdlib h gt   int num   atoi  23       23   If the string contains a decimal  the number will be truncated   int num   atoi  23 21       23

[c] How to convert an ASCII character into an int in C

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