#include <iostream>
#include <string>
#include <cctype>
#include <algorithm>
 
int main() {
    const std::string s1 { "f9c02b6c9da8943feaea4966ba7417d65de2fe7e" };
    std::string s2       { "........................................" };
    std::string s3       { "........................................" };
    std::string s4       { "........................................" };
    
    std::copy(cbegin(s1), cend(s1), begin(s2));
    std::cout << s2 << std::endl;
    
    std::copy_if(cbegin(s1), cend(s1), begin(s3), isalpha);
    std::cout << s3 << std::endl;
    
    std::copy_n(cbegin(s1), 10, begin(s4));
    std::cout << s4 << std::endl;
}