Write a program to solve quadratic equations \(ax^2 + bx + c = 0\). According to the so-called quadratic formula, real solutions to the quadratic equation given by \(a\), \(b\), and \(c\) exist if and only if the discriminant \(d = b^2 - 4ac\) satisfies \(d \geq 0\). The two solutions are given by: \[ r_1 = \frac{-b + \sqrt{d}}{2a} \] \[ r_2 = \frac{-b - \sqrt{d}}{2a} \] For the case of \(d = 0\), there is only one solution: \[ r_1 = r_2 = \frac{-b}{2a} \]

Write a function named quad in which, using the double-precision parameters \(a\), \(b\), and \(c\), the real solution(s) of the equation \(r_1\) (and \(r_2\)) is/are calculated if they exist. Return the number of real solutions (0, 1, or 2) from the quad function using the return statement.

In the main program, read the parameters \(a\), \(b\), and \(c\), and output the real solutions if they exist. Also, output the number of real solutions.

Important: The solutions of the equation should be calculated within the quad function using additional parameters passed by reference (call-by-reference). Output these solutions outside the function in the main program.

// Quadratic Equation: ax^2 + bx + c = 0 // Discriminant: d = b^2 - 4ac // Quadratic Formula: // r1 = (-b + sqrt(d)) / (2a) // r2 = (-b - sqrt(d)) / (2a) // Special Case (When d = 0): // r1 = r2 = -b / (2a)