Solving A QuadraticEquation by Java

Purpose: This program solves for the roots of a quadratic equation of the form a*x*x+b*x+c=0. It calculates the answers regardless of the type of roots that the equation possesses. import java.io.*; public class QuadraticEquation { //Define the main method. public static void main(String[] args) throws IOException { //Declare variables,and define each variable. double a; double b; double c; double discriminant; double imag_part; double real_part; double x1; double x2; //Create a buffered reader. BufferedReader inl=new BufferedReader(new InputStreamReader(System.in)); //Prompt the user for the coefficients of the equation. System.out.println("This program solves for the roots of quadratic equation."); System.out.println("Please input the coefficients of quadratic equation:"); System.out.print("Enter the coefficients A: "); a=Double.parseDouble(inl.readLine()); System.out.print("Enter the coefficients B: "); b=Double.parseDouble(inl.readLine()); System.out.print("Enter the coefficients C: "); c=Double.parseDouble(inl.readLine()); System.out.println("The quadratic equation you inputed is:"); System.out.println(a+"*x*x + "+b+"*x + "+c+" = 0"); //Caluate discriminant discriminant=b*b-4*a*c; //Solve for the roots,depending on the discriminant. if(discriminant>0) { //Two real roots x1=(-b+Math.sqrt(discriminant))/(2*a); x2=(-b-Math.sqrt(discriminant))/(2*a); System.out.println("This equation has two real roots:"); System.out.println("X1 = "+x1+" , X2 = "+x2); } else if(discriminant==0) { //One repeated root x1=(-b)/(2*a); System.out.println("This equation has repeated real roots:"); System.out.println("X1 = X2 = "+x1); } else { //Two complex root real_part=(-b)/(2*a); imag_part=Math.sqrt(Math.abs(discriminant))/(2*a); System.out.println("This equation has two Complex roots:"); System.out.println("X1 = "+real_part+"+"+imag_part+"i"); System.out.println("X2 = "+real_part+"-"+imag_part+"i"); } } }