// A class that represents quadratic functions, i.e., functions of
// the form
//   f(x) = ax^2 + bx + c

// History
//
//   January 2007 -- Created by Doug Baldwin as part of a prototype
//     solution to a CSci 240 exercise.




class Quadratic implements Function {
    
    
    
    
    // Internally, quadratic functions store their a, b, and c coefficients:
    
    private double a;
    private double b;
    private double c;
    
    
    
    
    // The constructor. This simply initializes the function's coefficients
    // from values provided by the client.
    
    public Quadratic( double a, double b, double c ) {
        this.a = a;
        this.b = b;
        this.c = c;
    }
    
    
    
    
    // Evaluate a quadratic function. The parameter to this method is the
    // x value at which to evaluate the function, and the return value is
    // the function's value at that x.
    
    public double value( double x ) {
        return a * x * x + b * x + c;
    }
    
    
    
    
    // Generate a string representation of a quadratic function.
    
    public String toString() {
        return a + " x^2  +  " + b + " x  +  " + c;
    }
}