islower()                Test for Lowercase
 
 #include   <ctype.h>
 
 int        islower(c);
 int        c;                           Integer value to be tested
 
    islower() tests if 'c' is lowercase ('a' - 'z').
 
    Returns:    True (nonzero) if the integer satisfies the test
                condition or false (zero) if it does not.  The result is
                undefined if 'c' is other than an ASCII character or EOF.
 
      Notes:    islower() is a macro.
 
  -------------------------------- Example ---------------------------------
 
    The following statement tests whether the character read from a file
    is lowercase.
 
         #include <ctype.h>
         #include <stdio.h>               /* for fopen */
 
         int ch;
         FILE *stream;
 
         main()
         {
             if ((stream = fopen("input.dat","r+"))!= NULL) {
                 while (!feof(stream)) {
                     if (islower(ch = getc(stream)))
                                 ;
                       /* process character */
                 }
             }
          }

Seealso:


 isalnum() 
 isalpha() 
 isascii() 
 isspace() 
 isupper()