1. Three ways of outputting an array
One-dimensional array:
define an array int[] array = {1,2,3,4,5};
(1) The traditional for loop method
for(int i=0;i<array.length;i++)
{
System.out.println(array[i]);
}
(2) for each loop
for(int a:array)
System.out.println(a);
(3) Use the toString method in the Array class
Calls Array.toString(a), which returns a string containing the elements of the array, enclosed in parentheses and separated by commas
int[] array = {1,2,3,4,5};
System.out.println(Arrays.toString(array));
Output: [1, 2, 3, 4, 5]
Description: System.out.println(array); This is not possible, so printing is the first address of the array.
Two-dimensional array:
For two-dimensional arrays, these three methods are also corresponding, define a two-dimensional array:
int[][]magicSquare =
{
{16,3,2,13},
{5,10,11,8},
{9,6,7,3}
};
Java does not actually have multi-dimensional arrays, only one-dimensional arrays. Multi-dimensional arrays are interpreted as "arrays of arrays". For example, a two-dimensional array magicSquare is a three-element array containing {magicSquare[0], magicSquare[1], magicSquare[2]}. Dimensional array, magicSqure[0] is a one-dimensional array containing four elements {16,3,2,13}, the same is true for magicSquare[1] and magicSquare[2] .
(1) The traditional for loop method
for(int i=0;i<magicSquare.length;i++)
{
for(int j=0;j<magicSquare[i].length;j++)
{
System.out.print(magicSquare[i][j]+" ");
}
System.out.println(); //换行
}
(2) for each loop
for(int[] a:magicSquare)
{
for(int b:a)
{
System.out.print(b+" ");
}
System.out.println();//换行
}
(3) Use the toString method in the Array class
for(int i=0;i<magicSquare.length;i++)
System.out.println(Arrays.toString(magicSquare[i]));