#include <stdio.h>
int main(void) {
    printf("1. Toi khong duoc phep chat trong lop.\n");
    printf("2. Toi khong duoc phep chat trong lop.\n");

    /* 996 chi dan printf. */

    printf("999. Toi khong duoc phep chat trong lop.\n");
    printf("1000. Toi khong duoc phep chat trong lop.\n");
    return 0;
}

File.open('trungphat.c', 'w') do |output|
  output.puts '#include <stdio.h>'
  output.puts 'int main(void) {'
  1.upto(1000) do |i|
    output.puts "    printf(\"#{i}. " +
      "Toi khong duoc phep chat trong lop.\\n\");"
  end
  output.puts '    return 0;'
  output.puts '}'
end

INPUT_FILE_NAME = 'ljlogo.png'
OUTPUT_FILE_NAME = 'ljlogo.h'
DATA_VARIABLE_NAME = 'ljlogo'

File.open(INPUT_FILE_NAME, 'r') do |input|
  File.open(OUTPUT_FILE_NAME, 'w') do |output|
    output.print "unsigned char #{DATA_VARIABLE_NAME}[] = {"
    data = input.read.unpack('C*')
    data.length.times do |i|
      if i % 8 == 0
        output.print "\n    "
      end
      output.print '0x%02X' % data[i]
      output.print ', ' if i < data.length - 1
    end
    output.puts "\n};"
  end
end

unsigned char ljlogo[] = {
    0x89, 0x50, 0x4E, 0x47, 0x0D, 0x0A, 0x1A, 0x0A,
    0x00, 0x00, 0x00, 0x0D, 0x49, 0x48, 0x44, 0x52,

    /* Khoảng vài trăm dòng ở đây. */

    0x0B, 0x13, 0x00, 0x00, 0x00, 0x00, 0x49, 0x45,
    0x4E, 0x44, 0xAE, 0x42, 0x60, 0x82
};

#include <stdio.h>
#include "ljlogo.h"

/* In dữ liệu của mảng ljlogo theo các giá trị byte hexadecimal . */
int main(void) {
    int i;
    for (i = 0; i < sizeof(ljlogo); i++) {
        printf("%X ", ljlogo[i]);
    }
    return 0;
}

x = 3
s = 'x + 1'
puts eval(s)

puts eval((1..100).to_a.join('+'))

f="f=%p;puts f%%f";puts f%f

ruby -e 'f="f=%p;puts f%%f";puts f%f' | ruby

class Person
  attr_accessor :name
end

class Person
  def name
    @name
  end
  def name=(new_name)
    @name = new_name
  end
end

cls.define_method(name) { body }

obj.instance_variable_set(name, value)

require 'generator'

class Object
  def Object.attr_initialize(*attrs)
    define_method(:initialize) do |*args|
      if attrs.length != args.length
        raise ArgumentError,
          "wrong number of arguments " +
          "(#{args.length} for #{attrs.length})"
      end
      SyncEnumerator.new(attrs, args).each do
        |attr, arg|
        instance_variable_set("@#{attr}", arg)
      end
    end
    attr_accessor *attrs
  end
end

class Student
  attr_initialize :name, :id, :address
end

s = Student.new('Erika', 123, '13 Fake St')
s.address = '13 Wrong Rd'
puts s.name, s.id, s.address

Erika
123
13 Wrong Rd