3-2.txt

java入门的几个代码,很实用,初学者不可错过

public class roots {
public static void main(String args[]) {
int a,b,c;
float x1,x2;
int check;
a=1;b=-2;c=1;
check=b*b-4*a*c;
if (check==0)
  {x1=(-b)/(2*a);
   x2=x1;
   System.out.println("x1="+x1);
   System.out.println("x2="+x2);
  }
else
  if (check>0) {
  x1=(-b+(float)Math.sqrt(check))/(2*a);
  x2=(-b-(float)Math.sqrt(check))/(2*a);
   System.out.println("x1="+x1);
   System.out.println("x2="+x2);
   }
  else
{    //读者自己填写
}
}
}
 }