1 import javax.swing.JOptionPane; 2 public class TheDirection { 3 public static void main(String[] args){ 4 double a,b,c,t,r1,r2; 5 String number; 6 int messageType=JOptionPane.INFORMATION_MESSAGE; 7 number=JOptionPane.showInputDialog(null,"输入a"); 8 a=Double.parseDouble(number); 9 number=JOptionPane.showInputDialog(null,"输入b"); 10 b=Double.parseDouble(number); 11 number=JOptionPane.showInputDialog(null,"输入c"); 12 c=Double.parseDouble(number); 13 t = b*b-4*a*c; 14 if(t>0){ 15 r1 = (-b+Math.pow(t,0.5))/(2*a); 16 r2 = (-b-Math.pow(t,0.5))/(2*a); 17 String message="The equation has two roots " + r1 + " and "+ r2; 18 JOptionPane.showMessageDialog(null,message,"result",messageType); 19 } 20 else if(t==0){ 21 r1 = (-b+Math.pow(t,0.5))/(2*a); 22 String message="The equation has one roots " + r1; 23 JOptionPane.showMessageDialog(null,message,"result",messageType); 24 } 25 else{ 26 String message="The equation has no real roots "; 27 JOptionPane.showMessageDialog(null,message,"result",messageType); 28 } 29 30 } 31 }