ctype library

#include <ctype.h>

• int isalnum(int iochar);
  returns true if iochar is either an alphabet character or a digit
• int isalpha(int iochar);
  returns true if iochar is an alphabet character
• int iscntrl(int iochar);
  returns true if iochar is a control character
• int isdigit(int iochar);
  returns true if iochar is digit
• int isgraph(int iochar);
  returns true if iochar is a printing character except space (' ')
• int islower(int iochar);
  returns true if iochar is an alphabet character that is lower case
• int isprint(int iochar);
  returns true if iochar is a printing character including space (' ')
• int ispunct(int iochar);
  returns true if iochar is a punctuation character
• int isspace(int iochar);
  returns true if iochar is a space (' ', '\t', '\n', '\f', '\r', '\v')
• int isupper(int iochar);
  returns true if iochar is an alphabet character that is upper class
• int isxdigit(int iochar);
  returns true if iochar is a hexidecimal digit
• int tolower(int iochar);
  returns the lower case version of iochar if there is one; otherwise, returns iochar
• int toupper(int iochar);
  returns the upper case version of iochar if there is one; otherwise, returns iochar