Java outputs a randomly generated number and outputs the maximum value matrix wherein the minimum

topic:

Write Java programs, input from the keyboard a positive integer n (n ≧ 2), generates a random matrix of order n, are integers each element, which is in the range [1,999]. Then the maximum and minimum output matrix elements.

public class 实验1_4 {

	public static void main(String[] args) {
		Scanner reader=new Scanner(System.in);
		int n=reader.nextInt();
		int[][] matrix=creatMatrix(n);
		FindMaxAndMinNumber(matrix);
	}
	public static int[][] creatMatrix(int n){
		int matrix[][]=new int[n][n];
		for(int i=0;i<n;i++)
		{
			for(int j=0;j<n;j++)
			{
				matrix[i][j]=randomNumber();
				System.out.print(matrix[i][j]+" ");
			}
			System.out.println();
		}
		return matrix;
	}
	public static int randomNumber() {
		int num=new Random().nextInt(1000);//顺带了解java中的Random函数；
		//public int nextInt(int n)
		//该方法的作用是生成一个随机的int值，
		//该值介于[0,n)的区间，也就是0到n之间的随机int值，包含0而不包含n
		return num;
	}
	public static int FindMaxAndMinNumber(int[][] matrix) {
		int max=0;int min=1000;
		for(int i=0;i<matrix.length;i++) {
			for(int j=0;j<matrix.length;j++) {
				if(matrix[i][j]>max) {
					max=matrix[i][j];
				}
				if(matrix[i][j]<min) {
					min=matrix[i][j];
				}
			}
		}
		System.out.println("max="+max);
		System.out.println("min="+min);
		return 0;
	}
}