The output functions are putchar and printf. Putchar can only output character constants and character variables, and printf can output various types of variables, so the answer is printf.

In addition, a pair of getchar and putchar operate on characters and character variables, and a pair of scanf and printf can input and output various types of variables. Let ch be a char variable and I be an integer variable. Usage is as follows.

input:c = getchar()； Scanf("%c ",& ampCh) (note &; Will often forget); scanf("%d "，& ampI)；

Output: putchar (c); printf("%c "，ch)； printf("%d "，I)；

Getchar () can accept all kinds of characters, including space carriage return, and the corresponding putchar can output a character, such as:

putchar(' a ')； Will type a on the screen, putchar can also type the value that already exists in the character variable ch:

c = ' aputchar(c)； The screen will also print an a, scanf and printf. Nothing special, just don't type it wrong. In addition, when inputting multiple variables, such as: scanf("%c, %d ",ch, i); At this time, you should also enter a comma, first enter' a', then enter',', and then enter 1. That's all.