# include & ltstdio.h & gtint？ main(){int？ n； scanf("%d "，& ampn)； while(n){ printf("%d "，n % 10)； ? n/= 10； }? .

-Space travel, an electronic game that simulates the navigation of the solar system. Behind the boss, he found a spare small computer-PDP-7.

But this computer doesn't have an operating system, so the game must use some functions of the operating system, so he began to develop an operating system for PDP-7. Later, this operating system was named UNICS (Unified Information and Computing Service).

1967, Martin Richards of Cambridge University simplified the CPL language, so BCPL (Basic Combinatorial Programming Language) was produced.

In the 1960s, at & amp； T company bell laboratories (at & amp； Ken Thompson, a researcher at T Bell Laboratories, has nothing to do, and his fingers itch, so he wants to play with one he made up.