This is nonsense. The error is here: > buffer[4] = '\n' — puts a newline at the last position > gets(buffer) — the function stops when it hits that newline B

This is nonsense. The error is here: > buffer[4] = '\n' — puts a newline at the last position > gets(buffer) — the function stops when it hits that newline But gets() doesn't stop when it hits that newline. It stops when a newline appears in the input stream, not in the buffer the input is being copied to. Besides, good luck finding a modern compiler that still supports gets() at all.