В одно слово переписать буквы а во второе прочие символы

#include <iostream>
#include <string>
using namespace std;
int main()
{
    string s;
    getline(cin, s);
    string word1="";
    string word2="";
    for (int i = 0; i < s.size(); i++)
    
        if (s[i] == '0' || s[i] == '1' || s[i] == '2' || s[i] == '3' || s[i] == '4' || s[i] == '5' || s[i] == '6' || s[i] == '7' || s[i] == '8' || s[i] == '9' )
            word2 += s[i];
        else
            word1 += s[i];
    
    if (!word1.empty())
        cout << "Word 1: " << word1 << "\n";
    else
        cout << "There was no letters in input\n";
 
    if (!word2.empty())
        cout << "Word 2: " << word2 << "\n";
    else
        cout << "There was no digits in input\n";
    system("pause");
    return 0;
}

if (s[i] >= '0' && s[i}<='9')

if (s[i] >= 'a' && s[i}<='z' || s[i] >= 'A' && s[i}<='Z')

string s, a, b;
    cin >> s;
    for (auto i : s) {
        if (isalpha(i))
            a += i;
        else b += i;
    }
    cout << a << endl << b;

#include <iostream>
#include <string>
using namespace std;
int main()
{
    string s;
    getline(cin, s);
    string word1 = "";
    string word2 = "";
    for (int i = 0; i < s.size(); i++)
 
        if (s[i] >= '0' && s[i] <='9')
            word2 += s[i];
        else if ((s[i] >= 'a' && s[i] <= 'z') || (s[i] >= 'A' && s[i] <= 'Z'))
            word1 += s[i];
 
    if (!word1.empty())
        cout << "Word 1: " << word1 << "\n";
    else
        cout << "There was no letters in input\n";
 
    if (!word2.empty())
        cout << "Word 2: " << word2 << "\n";
    else
        cout << "There was no digits in input\n";
    system("pause");
    return 0;
}

#include <iostream>
#include <string>
#include <iterator>
#include <algorithm>
 
int main()
{
   std::string letters, other, str{"12So1me beau!!!tifu!!ll t%e5xt"};
   std::partition_copy(str.cbegin(), str.cend(),
                       std::back_inserter(letters),
                       std::back_inserter(other),
                       ::isalpha);
   std::cout << letters << "\n" << other;