使用嵌套循环实现正方形打印（Square of Asterisks）

使用两层嵌套循环，实现行列循环打印输出，形成简单图案。

代码如下：

//JHTP Exercise 4.29:Square of Asterisks
//by pandenghuang@163.com
/**(Square of Asterisks) Write an application that prompts the user to enter the size of the side
of a square, then displays a hollow square of that size made of asterisks. Your program should work
for squares of all side lengths between 1 and 20.*/
import java.util.Scanner;

public class SquareOfAsterisks {

public static void main (String[] args){
Scanner input=new Scanner(System.in);
System.out.print("请输入要输出的正方形大小（整数）：");
int size=input.nextInt();
int number=1;
int sentinel=1;
while (sentinel<=size){
while (number<=size){
System.out.print("*");
number++;
}
System.out.print("\n");
number=1;
sentinel++;
}

}
}

运行截屏：

请输入要输出的正方形大小（整数）：10

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