编辑代码

class Main {
	public static void main(String[] args) {

      //一维数组赋值初始化，并调用内容
      {int day[]=new int[]{31,28,31,30,31,30,31,31,30,31,30,31};
      
      for(int i=0;i<12;i++){
          System.out.println((i+1)+"月有"+day[i]+"天");
        }
      }

      
     //二维数组
       {
         int a[][]=new int[3][4];
         for(int i=0;i<a.length;i++){
             for (int j=0;j<a[i].length;j++){
                 System.out.print(a[i][j]);
               }System.out.println();
            }
        }
        

        {
            String bookshelf[][]=new String[3][2];
            bookshelf[0][0] = "历史类读物";
            bookshelf[1][0] = "经济类读物";
            bookshelf[1][1] = "现代科学读物";
            for(int i=0;i<bookshelf.length;i++){
                for(int j=0;j<bookshelf[i].length;j++){
                    System.out.print("第"+(i+1)+"层"+"第"+(j+1)+"列"+bookshelf[i][j]);
                }System.out.println();
            }
        }


    }
}