Search in an Array of Rational Numbers without floating point arithmetic

// C# program for Binary Search for
// Rational Numbers without using
// floating-point arithmetic
using System;

class Rational {
    public int p;
    public int q; 
    
    public Rational(int num, int den) {
        p = num;
        q = den;
    }
}

class GfG {
    
    // Utility function to compare two
    // Rational numbers 'a' and 'b'.
    // It returns:
    //  0 --> When 'a' and 'b' are equal
    //  1 --> When 'a' is greater than 'b'
    // -1 --> When 'b' is greater than 'a'
    static int compare(Rational a, Rational b) {
        if (a.p * b.q == a.q * b.p)
            return 0;
        if (a.p * b.q > a.q * b.p)
            return 1;
        return -1;
    }
    
    // Returns the index of 'x' in the array 'arr' within the range [l, r]
    // if it is present, else returns -1.
    // It uses Binary Search for efficient searching.
    static int binarySearch(Rational[] arr, Rational x) {
        int l = 0, r = arr.Length - 1;
        
        while (l <= r) {
            int mid = l + (r - l) / 2;
    
            // If the element is present at the middle itself
            if (compare(arr[mid], x) == 0)
                return mid;
    
            // If the element is smaller than the middle element,
            // it can only be present in the left subarray
            if (compare(arr[mid], x) > 0)
                r = mid - 1;
    
            // Else, the element can only be 
            // present in the right subarray
            else
                l = mid + 1;
        }
    
        // Element is not present in the array
        return -1;
    }
    
    static void Main() {
        Rational[] arr = { new Rational(1, 5), 
        new Rational(2, 3), new Rational(3, 2),
        new Rational(13, 2) };
        Rational x = new Rational(3, 2);

        Console.WriteLine(binarySearch(arr, x));
    }
}