6F. Summary

A few functions, including sqrt, pow, abs, fabs, max, min, printf and scanf are available for you to use.

Typically, a program reads from the standard input and writes to the standard output.

By default, the standard input is tied to the keyboard and the standard output is tied to the terminal window. But you can redirect them to files.

Use printf to write to the standard output and scanf to read from the standard input.