When printing a single character in a C program, must I use "%1s" in the format string? Can I use something like "%c"?
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 */
As mentioned in one of the other answers, you can use putc(int c, FILE *stream), putchar(int c) or fputc(int c, FILE *stream) for this purpose.
What's important to note is that using any of the above functions is from some to signicantly faster than using any of the format-parsing functions like printf.
Using printf is like using a machine gun to fire one bullet.
Be careful of difference between 'c'
and "c"
'c'
is a char suitable for formatting with %c
"c"
is a char* pointing to a memory block with a length of 2 (with the null terminator).
char variable = 'x'; // the variable is a char whose value is lowercase x
printf("<%c>", variable); // print it with angle brackets around the character
The easiest way to output a single character is to simply use the putchar
function.
来源:https://stackoverflow.com/questions/310032/output-single-character-in-c