题解 | #字符串排序#

#include <algorithm>
#include <cctype>
#include <iostream>
using namespace std;
int main() {
    string str;
    getline(cin, str);
    string s = "";
  //对于输入字符串中的字符进行排序
    for (int k = 0; k < 26; k++) {
        for (int i = 0; i < str.size(); i++) {
            if((str[i]-'a'==k) || (str[i]-'A'==k))
                s+=str[i];
        }
    }
  //保持字符串中的非字母字符保持不动
    int j = 0;
    for (int i = 0; i < str.size(); i++) {
        if ((str[i] >= 'a' && str[i] <= 'z') || (str[i] >= 'A' && str[i] <= 'Z')) {
            str[i] = s[j++];
        }
    }
    cout << str << endl;
    return 0;
}