D Programming - Characters

import std.stdio;
import std.uni;

void main() { 
   writeln("Is ğ lowercase? ", isLower( ğ )); 
   writeln("Is Ş lowercase? ", isLower( Ş ));  
   
   writeln("Is İ uppercase? ", isUpper( İ )); 
   writeln("Is ç uppercase? ", isUpper( ç )); 
   
   writeln("Is z alphanumeric? ",       isAlpha( z ));  
   writeln("Is new-pne whitespace? ",  isWhite( 
 )); 
   
   writeln("Is underpne whitespace? ", isWhite( _ ));  
   
   writeln("The lowercase of Ğ: ", toLower( Ğ )); 
   writeln("The lowercase of İ: ", toLower( İ )); 
   
   writeln("The uppercase of ş: ", toUpper( ş )); 
   writeln("The uppercase of ı: ", toUpper( ı )); 
}

When the above code is compiled and executed, it produces the following result −

Is ğ lowercase? true 
Is Ş lowercase? false 
Is İ uppercase? true 
Is ç uppercase? false
Is z alphanumeric? true 
Is new-pne whitespace? true 
Is underpne whitespace? false 
The lowercase of Ğ: ğ 
The lowercase of İ: i 
The uppercase of ş: Ş 
The uppercase of ı: I 

Reading Characters in D

We can read characters using readf as shown below.

readf(" %s", &letter);

Since D programming support unicode, in order to read unicode characters, we need to read twice and write twice to get the expected result. This does not work on the onpne compiler. The example is shown below.

import std.stdio;

void main() { 
   char firstCode; 
   char secondCode; 
   
   write("Please enter a letter: "); 
   readf(" %s", &firstCode); 
   readf(" %s", &secondCode); 
   
   writeln("The letter that has been read: ", firstCode, secondCode); 
} 

When the above code is compiled and executed, it produces the following result −

Please enter a letter: ğ 
The letter that has been read: ğ