#include <iostream>
#include <string.h>
#include <conio.h>
#include <stdio.h>
#include <regex>

string Sortstr (str[mlength]);
sort(Sortstr.begin(), Sortstr.end());

int mlength = 100;
int main()
{

    char str[mlength];
    int length;

    cout << "Please enter a c-string: ";
    cin.getline(str,mlength,'n');
     regex pass1("^[a-zA-Z]+");
        while(!regex_match(str,pass1))
        {
          cout<<"Error"<<endl;
         cout << "Please enter a c-string: ";
           cin.getline(str,mlength,'n');
        }
string Sortstr (str[mlength]);
sort(Sortstr.begin(), Sortstr.end());
}