Statement requires expression of integer type ('double' invalid) - C++ : I have

    #include <iostream>
    #include <iomanip>
    using namespace std;
    
    int main ()
    {
        double score;
        
    
        cout << fixed << setprecision(2) << "Enter your grade score and I will give you a letter grade \n";
        cin >> score;
        
        if (score < 0 || score > 100)
            cout << "Enter a number less than 100 and greater than 0" << endl;
        
        switch (score)
        {
            case score > 90 :
                cout << score << "Grade: A";
            case score > 80 || case score < 90  :
                cout << score << "Grade: B";
            case score > 70 || case score < 80  :
                cout << score << "Grade: C";
            case score > 60 || case score < 70  :
                cout << score << "Grade: D";
            case score < 60 :
                cout << score << "Grade: F";
                
        }
    }


I kept getting 

> Statement requires expression of integer type ('double' invalid)


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#Questions 


**How would one go about and debug this further ?** 

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I'm open to any suggestions at this moment. 

Any hints/suggestions / helps on this be will be much appreciated! 
