字符串面试题（三）— 把一个字符串的大写字母放到字符串的后面

#include <stdio.h>
#include <string.h>
int main() {
  char s[1000], t;
  int i, j;
  while (scanf("%s", s) != EOF) {
    for (i = 1; i < strlen(s); ++i) {
      j = i;
      if ('a' <= s[i] && s[i] <= 'z')
        while (j != 0 && 'A' <= s[j-1] && s[j-1] <= 'Z') {
          t = s[j-1];
          s[j-1] = s[j];
          s[j--] = t;
        }
    }
    printf("%s\n", s);
  }
  return 0;
}