C#学习笔记之——数组

一、二维数组

定义举例：

 int[,] b = { { 1, 1 }, { 3, 4 } };

 int[,] c = new int[3, 3]{ { 1, 2, 3 }, { 4, 5, 6 }, { 7, 8 , 9 } };

 int[,] d = new int[, ]{ { 1, 2, 3 }, { 4, 5, 6 } };

若定义和赋值分开，可以这样做：

int[,] v;
v = new int[2,3];

和一维数组不同，二维数组的

Console.Write (b.Length);

输出的值是4，而且不能用这种遍历

将二维数组的行和列转换，并赋值给另一个二维数组：

int[,] c = new int[2, 3]{ { 1, 2, 3 }, { 4, 5, 6 } };
int[,] d = new int[3, 2];
for (int i = 0; i < 3; i++) {
	for (int j = 0; j < 2; j++) {
		d [i, j] = c [j, i];
	}
}
for (int i = 0; i < 3; i++) {
	for (int j = 0; j < 2; j++) {
		Console.Write (" {0}", d [i, j]);
	}
	Console.WriteLine ();
}

求对角线元素之和

int[,] a = { { 10, 12, 13 }, { 14, 15, 16 }, { 17, 18, 19 } }; 
int sum = 0;
for (int i = 0; i < 3; i++) {
	for (int j = 0; j < 3; j++) {
		if (i == j) {
			sum += a [i, i];	
		}
	}
}
Console.WriteLine (sum);

二、交错数组

数组里面放数组的感觉

定义：

int[] a = {1,2,3}, b = {4,5,6}, c = {7,8,9};
int[][] numbers = new int[3][];
int[][] number = new int[3][]{a,b,c};
int[][] number1 = new int[4][]{a,b,c,new int[]{4,9}};

输出：

int x = number [1] [1];
Console.WriteLine (x);

遍历输出：

for (int i = 0; i < number1.Length; i++) {
	for (int j = 0; j < number1 [i].Length; j++) {
		Console.Write (" {0}", number1 [i] [j]);
	}
	Console.WriteLine ();
}
//1 2 3
//4 5 6
//7 8 9
//4 9