Question

I got a problem about how to reverse a string containing this ‘abcd汉字efg’.

str_to_reverse = "abcd汉字efg"; /* those non-ASCII chars are Chinese characters, each of them takes 2 bytes */

after reversion, it should be:

str_toreverse = "gfe字汉dcba";

I thought, to reverse the string, I gotta identify those non-ASCII chars, because I think that simply reversing every byte won’t get the right answer.

How can I do it?

PS:
I wrote this program under Ubuntu, 32-bit.
then I printed every byte:

for(i = 0; i < strlen(s); i++)
    printf("%c", s[i]);

I got some gibberish text instead of “汉字”.

Answer 1

Pure C89 answer:

#include <stdlib.h>
#include <stdio.h>
#include <locale.h>
#include <string.h>

int main()
{
    char const* str;
    size_t slen;
    char* rev;

    setlocale(LC_ALL, "");
    str = "abcd汉字efg";
    printf("%s\n", str);
    slen = strlen(str);
    rev = malloc(slen+1)+slen;
    *--rev = '\0';
    while (*str != '\0') {
        int clen, i;
        clen = mblen(str, slen);
        if (clen == -1) {
            fprintf(stderr, "Bad encoding\n");
            return EXIT_FAILURE;
        }
        for (i = 0; i < clen; ++i) {
            *--rev = str[clen-1-i];
        }
        str += clen;
    }
    printf("%s\n", rev);
    return 0;
}