顺时针打印矩阵

题目：输入一个矩阵，按照从外向里的以顺时针的顺序依次打印出每一个数字。

例如如下矩阵 [ 1 ,2 ,3 4

                            5,6,7,8

    9,10,11,12

13,14,15,16}

则依次打出1,2,3,4,8,12,16,15,14,13,9,5,6,7,11,10

可以看出每次顺时针打印一圈，难点在于找到圈与圈之间的关系，注意到以左上角为(0,0)，以后依次每圈左上角的坐标都不变（start,start)

另外注意到当我们用二维数组传递至形参时候，形参必须指定二维长度。

#include<iostream>
using namespace std;
const int colums = 4,rows = 4;
void print(int a){
	cout<<a<<",";
}
void PrintCycle(int numbers[][colums], int columns, int rows, int start) {

	int endX = columns - 1 - start;
	int endY = rows - 1 - start;

	for (int j = start; j <= endX; j++) {
		print(numbers[start][j]);
	}
	for (int i = start + 1; i <= endY; i++) {
		print(numbers[i][endY]);
	}
	if (start < endX && start < endY) {
		for (int j = endX - 1; j >= start; j--) {
			print(numbers[endY][j]);
		}
	}
	if (start < endX && start < endY - 1) {
		for (int i = endY - 1; i > start; i--) {
			print(numbers[i][start]);
		}
	}
}
void PrintMatrixClockwisely(int numbers[][colums], int columns, int rows) {
	if (numbers == NULL || columns <= 0 || rows <= 0) {
		return;
	}
	int start = 0;
	while (columns > start * 2 && rows > start * 2) {
		PrintCycle(numbers, columns, rows, start);
		start++;
	}
}
int main() {
	int a[rows][colums] = { { 1, 2, 3, 4 }, { 5, 6, 7, 8 }, { 9, 10, 11, 12 }, { 13, 14,
			15, 16 } };
	PrintMatrixClockwisely(a, 4, 4);
	return 0;
}