#region 练习题一
int[,] arr1 = new int[100, 100];
int index = 1;
for (int i = 0; i < arr1.GetLength(0); i++)
{
    for (int j = 0; j < arr1.GetLength(1); j++)
    {
        arr1[i, j] = index;
        ++index;
    }
}
for (int i = 0; i < arr1.GetLength(0); i++)
{
    for (int j = 0; j < arr1.GetLength(1); j++)
    {
        Console.Write(arr1[i, j] + "\t");
    }
    Console.WriteLine();
}
#region clear
Console.ReadKey();
Console.Clear();
#endregion
#endregion

#region 练习题二
Console.WriteLine("练习题二");
int[,] arr2 = new int[6, 6];
Random r = new Random();
Console.WriteLine(arr2.GetLength(0) / 2 + " " + arr2.GetLength(1) / 2);
for (int i = 0; i < arr2.GetLength(0); i++)
{
    for (int j = 0; j < arr2.GetLength(1); j++)
    {
        if (i < arr2.GetLength(0)/2 && j+1 > arr2.GetLength(1)/2)
            arr2[i, j] = 0;
        else
            arr2[i, j] = r.Next(1, 11);
    }
}
for (int i = 0; i < arr2.GetLength(0); i++)
{
    for (int j = 0; j < arr2.GetLength(1); j++)
    {
        Console.Write(arr2[i, j] + "\t");//+" "+ i + j + 
    }
    Console.WriteLine();
}
#region clear
Console.ReadKey();
Console.Clear();
#endregion
#endregion

#region 练习题三
Console.WriteLine("练习题三");
int[,] arr3 = new int[3, 3];
int sum = 0;
for (int i = 0; i < arr3.GetLength(0); i++)
{
    for (int j = 0; j < arr3.GetLength(1); j++)
    {
        arr3[i, j] = r.Next(1,11);
        if (i == j)
            sum += arr3[i, j];
    }
}
for (int i = 0; i < arr3.GetLength(0); i++)
{
    for (int j = 0; j < arr3.GetLength(1); j++)
    {
        Console.Write(arr3[i, j] + "\t");
    }
    Console.WriteLine();
}
Console.WriteLine(sum);
#region clear
Console.ReadKey();
Console.Clear();
#endregion
#endregion

#region 练习题四
Console.WriteLine("练习题四");
int[,] arr4 = new int[3, 3];
sum = 0;
for (int i = 0; i < arr4.GetLength(0); i++)
{
    for (int j = 0; j < arr4.GetLength(1); j++)
    {
        arr4[i, j] = r.Next(1, 11);
        if (i == j)
            sum += arr4[i, j];
        else if (i + j == arr4.GetLength(1) - 1)
            sum += arr4[i, j];
    }
}
for (int i = 0; i < arr4.GetLength(0); i++)
{
    for (int j = 0; j < arr4.GetLength(1); j++)
    {
        Console.Write(arr4[i, j] + "\t");
    }
    Console.WriteLine();
}
Console.WriteLine(sum);
#region clear
Console.ReadKey();
Console.Clear();
#endregion
#endregion

#region 练习题五
Console.WriteLine("练习题五");
int[,] arr5 = new int[5, 5];
int max = 0;
int min = 11;
for (int i = 0; i < arr5.GetLength(0); i++)
{
    for (int j = 0; j < arr5.GetLength(1); j++)
    {
        arr5[i, j] = r.Next(1,11);
        if (arr5[i, j] > max)
            max = arr5[i, j];
        if (arr5[i, j] < min)
            min = arr5[i, j];
    }
}
for (int i = 0; i < arr5.GetLength(0); i++)
{
    for (int j = 0; j < arr5.GetLength(1); j++)
    {
        Console.Write(arr5[i, j] + "\t");
    }
    Console.WriteLine();
}
Console.WriteLine(max);
Console.WriteLine(min);
#region clear
Console.ReadKey();
Console.Clear();
#endregion
#endregion

#region 练习题六
Console.WriteLine("练习题六");
int m = 5, n = 5;
int[,] arr6 = new int[m, n];
//bool类型的数组默认值是false，所以可以用来标记某个位置是否被访问过
bool[] hang = new bool[m];
bool[] lie = new bool[n];
for (int i = 0; i < arr6.GetLength(0); i++)
{
    for (int j = 0; j < arr6.GetLength(1); j++)
    {
        arr6[i, j] = r.Next(0, 2);
        Console.Write(arr6[i, j] + "\t");
        if (arr6[i, j] == 1)
        {
            hang[i] = true;
            lie[j] = true;
        }
    }
    Console.WriteLine();
}
Console.WriteLine("分割");
for (int i = 0; i < arr6.GetLength(0); i++)
{
    for (int j = 0; j < arr6.GetLength(1); j++)
    {
        if (hang[i] == true || lie[j] == true)
        {
            arr6[i, j] = 1;
        }
        Console.Write(arr6[i, j] + "\t");
    }
    Console.WriteLine();
}

#endregion