<p>When printing a single character in a C program, must I use "%1s" in the format string? Can I use something like "%c"?</p>

yes,
```
%c
```
will print a single char:
```
```
printf("%c", 'h');
```
```
also,
```
putchar
```
/
```
putc
```
will work too. From "man putchar":
```
```
#include <stdio.h>

int fputc(int c, FILE *stream);
int putc(int c, FILE *stream);
int putchar(int c);

* fputc() writes the character c, cast to an unsigned char, to stream.
* putc() is equivalent to fputc() except that it may be implemented as a macro which evaluates stream more than once.
* putchar(c); is equivalent to putc(c,stdout).
```
```
EDIT:
Also note, that if you have a string, to output a single char, you need get the character in the string that you want to output. For example:
```
```
const char *h = "hello world";
printf("%c\n", h[4]); /* outputs an 'o' character */
```
```