题解 | #字符串排序# 字符串stl的使用

#include <algorithm>
#include <iostream>
using namespace std;

string s;
char res[1000];

bool cmp(char a, char b)
{
    if(a >= 'A' && a <= 'Z') a += 32; 
    if(b >= 'A' && b <= 'Z') b += 32; 
    return a < b;
}

bool isletter(char a)
{
    if(a >= 'A' && a <= 'Z' || (a >= 'a' && a <= 'z')) return true;
    return false;
}

int main() {
    while(getline(cin, s))
    {
        string t = "";
        for(int i = 0; i < s.size(); i++)
        {
            if(isletter(s[i])) t += s[i];
        }
        stable_sort(t.begin(), t.end(), cmp);

        for(int i = 0; i < s.size(); i++)
        {
            if(!isletter(s[i])) t.insert(t.begin() + i, s[i]);
        }

        cout << t << endl;
    }
}