Synchronization of old projects

Part1

C#基础/Lesson3_二维数组练习题/Lesson3_二维数组练习题.csproj

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+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <TargetFramework>net8.0</TargetFramework>
+    <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
+  </PropertyGroup>
+
+</Project>

C#基础/Lesson3_二维数组练习题/Program.cs

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+#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