import java.util.Scanner;
class larry{
public static void main(String[] args){
Scanner sc = new Scanner(System.in);
int a,b,c,d,e;
while(sc.hasNext()){
a=sc.nextInt();
b=sc.nextInt();
c=sc.nextInt();
if ( Math.pow(b,2) - 4*a*c >0){
d=(Math.sqrt(b*b-4*a*c))/(2*a);
e=(-Math.sqrt(b*b-4*a*c))/(2*a);
System.out.println("Two different roots x1="+d+"x2="+e);
}
else if (Math.pow(b,2)-4*a*c=0){
System.out.println("Two same roots");
}
else
System.out.println( "No real root");
}
}
}

 後來在網路上查完改寫的～～可是感覺很多多於步驟...

import java.util.Scanner;

class larry{

public static void main(String[] args){

Scanner sc = new Scanner(System.in);

int a,b,c;

double T;

int A,d,e;

while(sc.hasNext()){

a=sc.nextInt();

b=sc.nextInt();

c=sc.nextInt();

T=Math.sqrt(b*b - 4*a*c);

A=(int)Math.floor(T);

d=(-b+A)/(2*a);

e=(-b-A)/(2*a);

if ( b*b - 4*a*c >0){

System.out.println("Two different roots x1="+d+" , x2="+e);

}

else if (b*b-4*a*c==0){

System.out.println("Two same roots x="+d);

}

else

System.out.println( "No real root");

}

}

}