在JAVA中大概为利用System.in.read输入

import java.io.*;
public class sample { 
    public static void main(String[] args) throws IOException{
        byte a[]=new byte[50];
        String b;
        double c=0.0;
        
        System.in.read(a);
        b=new String(a,0);  //b转换成String对象str
        c=Double.parseDouble(b.trim());     //数字串转换成整数
        System.out.println(c);
    
    }

}