Control-C else, typically returning control to the user. Ctrl-C was one of a handful of keyboard sequences chosen by the program designers at Xerox PARC to control text editing, with Ctrl-Z (Undo), Ctrl-X (Cut), Ctrl-V (Paste), and Ctrl-P (Print). The first four letters are all located together at the left end of the bottom row of the standard QWERTY keyboard, and P towards the upper right. The equivalent key combination on Macintosh computers is Command-C. Control-C as an abort command was popularized by TOPS-20 and TOPS-10 and adopted by other systems including Unix. It was also adopted by Digital Equipment operating
Keyboard layout holding a modifier key with one hand leaves the other hand free to strike another key. An alphanumeric key labeled with only a single letter (usually the capital form) can generally be struck to type either a lower case or capital letter, the latter requiring the simultaneous holding of the key. The key is also used to type the upper of two symbols engraved on a given key, the lower being typed without using the modifier key. The English alphanumeric keyboard has a dedicated key for each of the letters A–Z, along with keys for punctuation and other symbols. In