Formatted Output

1. We have already seen that this is trivial with format specifiers:

   import std.stdio;
   
   void main() {
       writeln("(Enter 0 to exit the program.)");
   
       while (true) {
           write("Please enter a number: ");
           long number;
           readf(" %s", &number);
   
           if (number == 0) {
               break;
           }
   
           writefln("%1$d <=> %1$#x", number);
       }
   }
   

2. Remembering that the % character must appear twice in the format string to be printed as itself:

   import std.stdio;
   
   void main() {
       write("Please enter the percentage value: ");
       double percentage;
       readf(" %s", &percentage);
   
       writefln("%%%.2f", percentage);
   }