stdio.h

`stdio.h` is a foundational library in C programming that provides functions for input and output operations. It enables programs to interact with users and external data by allowing them to read data from devices like keyboards or files, and send data to screens or save to files. Key functions include `printf` for displaying information, `scanf` for receiving input, and file-handling functions such as `fopen`, `fclose`, `fread`, and `fwrite`. Including `stdio.h` in a program ensures these standard input/output capabilities are available, making user communication and data management straightforward.