Help with password requirements code.

[Adalaide]

I have been doing wicked good lately thanks to all the help I've been getting here but I am having some issues with this code. I am trying to write a code that "Output "Valid" if input contains fewer than 6 numbers and input's length is less than or equal to 8. Otherwise, output "Invalid"."
I feel like I need a npos somewhere but I can't figure out where because I am so new.

#include <iostream>
using namespace std;

int main() {
   bool isValidPasswd;
   string keyStr;

   cin >> keyStr;
if ((keyStr.length(<=8)&&(keyStr(isdigit(<6)){
    isValidPassword = true;
}
    else {
       isValidPassword = false;
    }
   if (isValidPasswd) {
      cout << "Valid" << endl;
   }
   else {
      cout << "Invalid" << endl;
   }
   
   return 0;
}

[againtry]

#include <iostream>

using namespace std;

int main()
{
    bool isValidPasswd{true};
    string keyStr;
    cin >> keyStr;
    if (keyStr.length() <= 8)
    {
        isValidPasswd = false;
    }
    
    int count{0};
    for(int i = 0; i < keyStr.length(); i ++)
    {
        if( std::isdigit(keyStr[i]) )
           count++;
    }
    
    if( count < 6 )
        isValidPasswd = false;
    
    if( isValidPasswd == true)
        cout << "Valid" << endl;
    else
        cout << "Invalid" << endl;
    
    return 0;
}

[againtry]

Or:

#include <iostream>

using namespace std;

int main()
{
    bool isValidPasswd{false};
    string keyStr;
    cin >> keyStr;
    
    int count{0};
    for(int i = 0; i < keyStr.length(); i ++)
    {
        if( std::isdigit(keyStr[i]) )
           count++;
    }
    
    if (keyStr.length() >= 8 and count >= 6)
    {
        isValidPasswd = true;
    }
    
    if( isValidPasswd == true)
        cout << "Valid" << endl;
    else
        cout << "Invalid" << endl;
    
    return 0;
}

[seeplus]

Valid - if input < 6 digits and inputLength <= 8 ?? Seems a queer valid requirement. Just a single 'a' or <space> would satisfy this. Have you got valid/invalid the wrong way round?

Assuming as given, then:

#include <iostream>
#include <algorithm>
#include <cctype>

int main() {
    std::string keyStr;

    std::cin >> keyStr;

    const bool isValidPasswd {keyStr.length() <= 8 && std::count_if(keyStr.begin(), keyStr.end(), [](unsigned char ch) {return std::isdigit(ch); }) < 6};

    std::cout << (isValidPasswd ? "Valid\n" : "Invalid\n");
}