import java.util.Scanner;
import java.util.Date;public class People {
//int,Date,String,double后面加[]是什么作用?或者说,java中[]有哪些用处?
private int[] age;
private Date[] birthday;
private String[] sex;
private double[] height;
private double[] weight;
public People(int n){//解释下int[n],double[n],String[n],Date[n]。
this.age = new int[n];
this.weight = new double[n];
this.sex = new String[n];
this.birthday = new Date[n];
Scanner in = new Scanner(System.in);//解释下System.in,及其逻辑含义
for(int i=0;i<n;i++){
System.out.println("Please input the age,height,weight,sex,and birthday");
age[n] = in.nextInt();
height[n] = in.nextDouble();
weight[n] = in.nextDouble();
sex[n] = in.next();
birthday[n] = new Date(in.nextInt(),in.nextInt(),in.nextInt());
}
}
}
import java.util.Date;public class People {
//int,Date,String,double后面加[]是什么作用?或者说,java中[]有哪些用处?
private int[] age;
private Date[] birthday;
private String[] sex;
private double[] height;
private double[] weight;
public People(int n){//解释下int[n],double[n],String[n],Date[n]。
this.age = new int[n];
this.weight = new double[n];
this.sex = new String[n];
this.birthday = new Date[n];
Scanner in = new Scanner(System.in);//解释下System.in,及其逻辑含义
for(int i=0;i<n;i++){
System.out.println("Please input the age,height,weight,sex,and birthday");
age[n] = in.nextInt();
height[n] = in.nextDouble();
weight[n] = in.nextDouble();
sex[n] = in.next();
birthday[n] = new Date(in.nextInt(),in.nextInt(),in.nextInt());
}
}
}
java一切皆引用,this.age = new int[n];就产生了n个引用了:age[0],age[1]....age[n-1],那些引用最终指向int类型的数据
System.in 是标准输入流,上面程序还出现了System.out 标准输出流,以后你还会见到System.err
System.in 是一种标准(键盘)的i/O 输入流,可以读取信息,但不能写它
定义了int类型数组,数组的长度是X
譬如:int[] a = new int[3];
定义了3个长度的数组即a[0],a[1],a[2]
分别定义一个int 、Date、String 、double类型的数组;解释下int[n],double[n],String[n],Date[n]。
this.age = new int[n];
this.weight = new double[n];
this.sex = new String[n];
this.birthday = new Date[n];为刚才定义的数据分配空间 ;Scanner in = new Scanner(System.in);//解释下System.in,及其逻辑含义System.in 是PrintStream的一个实例
只能 按字节读取。因此默认情况下,无法读取char数据。你可以使用 InputStreamReader 来包装 System.in对象,这样就可以 读取到 char类型了。