#include <stdio.h>int putchar(int ch);
The putchar( ) function writes the character contained in the least significant byte of ch to stdout. It is functionally equivalent to putc(ch, stdout). Because character arguments are elevated to integer at the time of the call, you can use character values as arguments to putchar( ).
The putchar( ) function returns the character written if successful, or EOF if an error occurs.
A related function is putc( ).