The getchar function proved convenient when you wanted to read data from a single character at a time.You saw how you could develop a function called readLine to read an entire line of text from your terminal. This function repeatedly called getchar until a newline character was read.
There is an analogous function for writing data to the terminal a single character at a time. The name of this function is putchar.
A call to the putchar function is quite simple: The only argument it takes is the char-acter to be displayed. So, the call
in which c is defined as type char, has the effect of displaying the character contained in c.
has the effect of displaying the newline character, which, as you know, causes the cursor to move to the beginning of the next line.
Source: Kochan Stephen G. (2004), Programming in C: A Complete Introduction to the C Programming Language, Sams; Subsequent edition.