>>191 再帰関数でよければ・・・

#include <stdio.h>
char *sort(char *c){return *(c+1)!=0?sort(c+1),(*c>*(c+1) ? *c^=*(c+1),*(c+1)^=*c,*c^=*(c+1):c),sort(c+1):c;}
void sort_ch(char *c){return sort(c);}

main (void) {
char s[32]="/tech/1162771475/";
sort_ch(s);
printf("%s\n",s);
}