Charles Babbage first introduced the concept of programmable machines in the early 19th century, though he did not envision desktop or laptop computers. The first general-purpose electronic computer was ENIAC, created in 1946 by John Mauchly and J. Presper Eckert to perform complex calculations. Computers have evolved significantly since then, becoming smaller from room-sized machines to today's laptops and tablets. Peripheral devices like keyboards, mice, printers and monitors were also invented to allow users to input data and see output from computers.