// some basics of characters

public class chars0 {
    public static void main(String[] args) {

	// Characters use the primitive type $char$:
	char value = 'a';
	
	// Characters are NOT equivalent to the values inside the $''$:
	char x = '0';
	if (x == 0) System.out.println("That shouldn't have happened.");

	// Character codes are also integers:
	System.out.println((int) value); // the letter 'a' is code 97
	    
	// To go from $int$ to $char$, use a $char$ cast:
	System.out.println((char) 97); // the letter 'a' is code 97

	// When operating on $char$s and $int$s, Java promotes the quantity
	// to $int$:
	System.out.println('a'+1);
	
	// Characters can use the ASCII numbering system (0 to 127):
	// "printing" characters (keyboard characters):
	System.out.println();
	for(int i=32;i<126;i++) 
	    System.out.print((char) i);

	// Sometimes you may print out "extended ASCII":
	System.out.println();
	for(int i=128;i<257;i++) 
	    System.out.print((char) i);
	
	// Example of "nonprinting" character (the bell):
	System.out.println((char) 7);

	// There is no "empty" character:
	// char z = ''; // illegal!
	// But, there is a character called NUL:
	System.out.println( (char) 0 ); // doesn't do much
	// This value is also the default value of a $char$ instance variable.

	// Handy trick for converting upper and lower cases:
	// 'A' = 65, 'a' = 97 --> 'a'-'A'=32
	System.out.println( (char)( 'd' - ('a'-'A')) ); // convert to uppercase

    }

}

/* output:

   97
   a
   98
   
    !"#$%&'()*+,-./0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_`
   abcdefghijklmnopqrstuvwxyz{|}
    ¡¢£¤¥¦§¨©ª«¬­®¯°±²³´µ¶·¸¹º»¼½¾¿ÀÁÂÃÄÅÆÇÈÉÊËÌÍÎÏÐÑÒÓÔÕÖ×ØÙÚÛÜÝÞßàáâãäåæ
   çèéêëìíîïðñòóôõö÷øùúûüýþÿ?
   
   D

*/