Java 用循环打印正方形

Printing a Square with loops

提问by user3040990

//college work

//大学工作

Hello, I am trying to print a square by using loops, it also require the user to input the height and width. The Output should look like this

您好，我正在尝试使用循环打印一个正方形，它还需要用户输入高度和宽度。输出应如下所示

....
.  .
....

any help would be apprciated

任何帮助都会得到认可

import java.util.Scanner;
public class Ex1 {
    public static void main(String[] args) {

        Scanner input = new Scanner(System. in );
        System.out.print("Please enter the height of the box: ");
        int x = input.nextInt();

        System.out.println("Please enter a width for the box: ");
        int y = input.nextInt();
        drawbox(x, y);

    }

    static void drawbox(int x, int y) {

        for (int j = 0; j < y; j++) {
            System.out.println("*");

            System.out.println();
            for (int i = 0; i < x - 2; i++) {
                System.out.print("*");
                for (int z = 0; z < y - 2; z++) {
                    System.out.print(" ");
                }
                System.out.println("*");

                for (int i = 0; j < y; j++) {
                    System.out.println("*");
                }

            }
        }
    }
}

采纳答案by Masudul

Change your loop from

改变你的循环

for(int i = 0; j<y ; j++){
      System.out.println("*");
 }

To

到

 for(int j = 0; j<y ; j++){
      System.out.println("*");
 }

---

---

To draw rectangle, change your drawbox code like:

要绘制矩形，请更改您的 drawbox 代码，例如：

static void drawbox(int x, int y) {
    for (int i = 0; i < y; i++) {
        System.out.print("*");
    }
    System.out.println();
    for (int i = 0; i < x - 2; i++) {
        System.out.print("*");
        for (int j = 0; j < y - 2; j++) {
            System.out.print(" ");
        }
        System.out.println("*");
    }
    for (int i = 0; i < y; i++) {
        System.out.print("*");
    }
    System.out.println();
}

回答by Le Duy Khanh

change

改变

  for(int i = 0; j<y ; j++){
      System.out.println("*");
 }

  for(int i = 0; j<y ; j++){
      System.out.println("*");
 }

to

到

  for(int i = 0; i<y ; i++){
      System.out.println("*");
 }

  for(int i = 0; i<y ; i++){
      System.out.println("*");
 }

回答by Sionnach733

You could use this(see below). this will print *'s for the first and last row. for the middle rows, it prints a star followed by spaces and closes with a star. It also has another method allStarswhich reuses code for first and last lines.

你可以使用这个（见下文）。这将为第一行和最后一行打印 *。对于中间的行，它打印一个星号，后跟空格并以星号结束。它还有另一种方法allStars，可以重用第一行和最后一行的代码。

static void drawbox(int height, int width){
    for (int i = 1; i <= height; i++) {
        if(i==1 || i==height){
            allStars(width);
        }else{
            System.out.print("* ");
            for(int k = 2; k < width; k++){
                System.out.print("  ");
            }
            System.out.print("*");
            System.out.print("\n");
        }
    }
}
static void allStars(int width){
    for(int k = 1; k <= width; k++){
        System.out.print("* ");
    }
    System.out.print("\n");
}

回答by Ruchira Gayan Ranaweera

Your solution was good enough when issue fixed. But take this as easy way, hope you will get some idea from this

问题解决后，您的解决方案已经足够好了。但是把这个当作简单的方法，希望你能从中得到一些想法

private static void printSquare(int width,int length){
      for(int i=0;i<width;i++){
          StringBuilder stringBuilder=new StringBuilder();
          stringBuilder.append("* ");
          for (int j=2;j<length;j++){
              if(i==0){
                stringBuilder.append("* ");
              }else if(i==width-1){
                stringBuilder.append("* ");
              }else {
                stringBuilder.append("  ");
              }
          }
          stringBuilder.append("* ");
          System.out.println(stringBuilder);
      }
}

When printSquare(5,5);, Out put

当printSquare(5,5);, 输出

* * * * * 
*       * 
*       * 
*       * 
* * * * * 

回答by Frank Ngai

A simple algorithm to draw square by loops

一种循环绘制正方形的简单算法

public void draw(int length){
    for(int i = 0; i < length; i++){
        for(int j = 0;j < length; j++){
            if(i!= 0 && j > 0 && i!= length - 1 && j!= length-1){
                System.out.print(" ");
            }
            else System.out.print("*");
        }
        System.out.println();
    }
}

回答by Jim Cyril

Try this one:

试试这个：

import java.util.Scanner;

    public class Rectangle {
        public static void main(String args[]){
             Scanner input = new Scanner(System. in );
                System.out.print("Please enter the height of the box: ");
                int x = input.nextInt();

                System.out.print("Please enter a width for the box: ");
                int y = input.nextInt();
                drawbox(x, y);

            }

            static void drawbox(int x, int y) {

                for (int j = 0; j < y; j++) {
                    System.out.print("* ");
                }
                System.out.println();
                    for (int i = 0; i < x; i++) {
                        System.out.print("* ");
                        for (int z = 0; z < y - 2; z++) {
                            System.out.print("  ");
                        }
                        System.out.println("*");
                        }

                        for (int k = 0; k < y; k++) {
                            System.out.print("* ");
                        }

                }    

        }

Output:

输出：

Please enter the height of the box: 10
Please enter a width for the box: 10
* * * * * * * * * * 
*                 *
*                 *
*                 *
*                 *
*                 *
*                 *
*                 *
*                 *
*                 *
*                 *
* * * * * * * * * *