function.cpp

int digit_count(int n) {
    if (n == 0) return 1;
    return (int)(log10(n)) + 1;
}

vector<string> name_file(int len,const string &folder, const string &prefix,const string &suffix, int width = 1){
    width = max(digit_count(len),width);
    vector<string> files(len);

    for(int i=0;i<len;i++) {
        files[i] = folder + prefix + string(width - digit_count(i), '0') + to_string(i)+ suffix;
    }
    return files;
}

ofstream& n_integers(ofstream& out,int n){
    for(int i=0;i<n;i++){
        int a = a_dis(rng);
        out<<a<<' ';
    }out<<'\n';
    return out;
}

string str_make(int n,char base='a'){
    string out;out.reserve(n);

    for(int i=0;i<n;i++){
        out.push_back(char(char_dis(rng)+base));
    }
    return out;
}