Ключевые слова: abstract, access, background, barcode, bright, buildings, business, cell, cellphone, code, computer, connection, convenient, coupon, device, digital, display, e coupon, electronic, fast, gadget, hand, holding, information, man, message, mobile, modern, outside, people, phone, portable, qr, qrcode, quick response, reader, scan, screen, shopping, show, smart, smartphone, tablet, technology, telephone, touch, white,