- $ cat ./20.c
- #include <ctype.h>
- #include <stdio.h>
- int main() {
- char ch; ch = '\20';
- printf("is byte \"%c\" NULL?\n", ch);
- if (ch == '\0') {
- printf("yes, ch = \\%o\n", ch);
- } else if (isascii(ch)) {
- printf("no (but is ascii), ch = '%c'\n", ch);
- } else {
- printf("no, ch = \\%o\n", ch);
- }
- }
- $ gcc ./20.c -o 20
- $ ./20
- is byte "" NULL?
- no (but is ascii), ch = ''