java回形数

public class huixingshu {
    public static void main(String[] args) {
        Scanner scanner=new Scanner(System.in);
        System.out.print("请输入一个数字：");
        int num=scanner.nextInt();
        int sum=1;
        int [][]arr=new int[num][num];
        for (int n=1;n<=2*num-1;n++){
            if (n%4==1){
                    for (int j=n/4;j=n/4;j--){
                    arr[arr.length-1-n/4][j]=sum;
                    sum++;
                }

            }
            if (n%4==0){
                for (int i=arr.length-1-n/4;i>=n/4;i--){
                    arr[i][n/4-1]=sum;
                    sum++;
                }
            }

        }

        for (int i=0;i

 运行结果图：