How can I edit my script to exclude capital letters A to Z? : Starts with 0 -> 9 -> A -> Z -> a -> z then begins the next sequence of 00 -> zz

I'd like to remove the A -> Z section of my code so the output goes from 0 -> 9 -> a -> z without counting A -> Z.

    #include <iostream>
    #include <vector>
    using namespace std;
    void Crack(string password, vector<char> Chars)
    {
     cout<<"PASSWORD TO CRACK: "<<password<<endl;
     int n = Chars.size();
     int i = 0;
     while(true)
     {
     i++;
     int N = 1;
     for(int j=0;j<i;j++)N*=n;
     for(int j=0;j<N;j++)
     {
     int K = 1;
     string crack = "";
     for(int k=0;k<i;k++)
     {
     crack += Chars[j/K%n];
     K *= n;
     }
     cout<< "Testing PASS: "<<crack<<" "<<"against "<<password<<endl;
     if(password.compare(crack) == 0){
     cout<<"Cracked password: "<<crack<<endl;
     return;
     }
     }
     }
    }
    int main()
    {
     vector<char> Chars;
     for(char c = '0';c<='z';c++){
     if(isalpha(c) || isdigit(c))Chars.push_back(c);
     }
     Crack("zzzzzzzz", Chars);
    }**strong text**