ex4_16.java

判断三角形

//4.16（平方根的近似求法）
import javax.swing.JOptionPane;
public class Ex4_16{
  public static void main (String[] args) {
  	 double num=Double.parseDouble(JOptionPane.showInputDialog("请输入进行求根运算的数："));
  	 double sqrtofnum=sqrt(num);
  	 JOptionPane.showMessageDialog(null,"该数的平方根为："+sqrtofnum);
     System.exit(0);
  }
  public static double sqrt(double num){
    double nextGuess=1,lastGuess=0;
    while(Math.abs(nextGuess-lastGuess)>0.0001){
         lastGuess=nextGuess;
         nextGuess=(lastGuess+(num/lastGuess))/2;
    }
    return nextGuess;
  }
}