Question

//想要打印出一帧星号。框架整体上必须有16个星号。

public class Patterns {

    public static void main(String[] args) {

for(int i=1; i<=4; i++){
        for(int j=1; j<=4; i++){
            if((i==1||i==4)&&(j==1||j==4)){
                System.out.print("*");
            }
            else{
                    System.out.print(" ");
                }
            System.out.println();
            }

        }

    } 

}

Answer 1

这是一个允许您指定宽度和高度的版本：

int width = 5;
int height = 5; 
for (int i = 0; i < height; i++) {
    for (int j = 0; j < width; j++) {
        if (i == 0 || i == height -1) { //first or last line
            System.out.print("*");
        } else if (j == 0 || j == width -1) { // middle line first or last star
            System.out.print("*"); 
        } else { // middle line not on the edge
            System.out.print(" "); 
        }
    }
    System.out.println(); // start a new line
}

Answer 2

问题出在if条件 -

if((i==1||i==4)&&(j==1||j==4)){
 System.out.print("*");
}

更好的是，您可以尝试更强大的解决方案。您可以在此设置ROW和COLUMN来调整框架高度或宽度。使用以下代码，您可以打印矩形框，例如ROW = 15和COLUMN = 10。请参阅此处的解决方案 -

public class Frame{

    /*You may adjust ROW or COLUMN
    * You may print a rectangular frame
    * by setting ROW = 6 and COLUMN = 12
    */
    private final static int ROW = 4; 
    private final static int COLUMN = 4;

    //Need not to change
    private final static int I_MIN = 1;
    private final static int I_MAX = ROW;
    private final static int J_MIN = 1;
    private final static int J_MAX = COLUMN;

    public static void main(String[] args) {

        //always start from i=1 and j=1
        for(int i=1; i<=ROW; i++){
            for(int j=1; j<=COLUMN; j++){

                if(isOnMargin(i,j)){
                    System.out.print("*");
                }else{
                    System.out.print(" ");
                }

            }
            System.out.println();
        }
    }//main()

    /*
    * This method determine whether an (i,j) 
    * is on margin. In main method if an (i,j)
    * on margin then print "*" or print " ".
    */
    private static boolean isOnMargin(int i, int j){

        if(i==I_MIN || i==I_MAX){
            return true;
        }
        else if(j==J_MIN || j==J_MAX){
            return true;
        }
        return false;
    }

}

希望它会有所帮助非常感谢。

<强>输出：
4x4 frame

嵌套循环。想要打印出星号框架

2 个答案: