增加C#第3题

data/1..NET初阶/2.C#语法/2.C#文本值和变量/Variable.json

+{
+    "type": "code_options",
+    "author": "huanhuilong",
+    "source": "Variable.md"
+}
\ No newline at end of file

data/1..NET初阶/2.C#语法/2.C#文本值和变量/Variable.md

+# 隐式变量的类型
+
+C# 允许使用关键字`var`隐式声明变量的类型。例如下面两个语句等价：
+
+```csharp
+string user = "machine";
+var user = "machine";
+```
+
+以下代码中的四个`var`声明的变量，对应的C#类型分别是什么？
+
+```csharp
+var e = 'c'; 
+var f = 10;
+var g = 10.2m;
+var h = true;
+```
+
+## 答案
+
+```csharp
+char e = 'c';
+int f = 10;
+decimal g = 10.2m;
+bool h = false;
+```
+
+## 选项
+
+### A
+
+```csharp
+string e = 'c';
+int f = 10;
+decimal g = 10.2m;
+bool h = false;
+```
+
+### B
+
+```csharp
+char e = 'c';
+int f = 10;
+float g = 10.2m;
+bool h = false;
+```
+
+### C
+
+```csharp
+char e = 'c';
+int f = 10;
+decimal g = 10.2m;
+boolean h = false;
+```

data/1..NET初阶/2.C#语法/2.C#文本值和变量/config.json

@@ -3,6 +3,7 @@
   "keywords": [],
   "children": [],
   "export": [
-      "String.json"
+      "String.json",
+      "Variable.json"
   ]
 }
\ No newline at end of file

data/1..NET初阶/2.C#语法/2.C#文本值和变量/sample/Program.cs

 // See https://aka.ms/new-console-template for more information
 
-Console.WriteLine("Hello, World!");
+// Console.WriteLine("Hello, World!");
 
-string helloworld1 = "Hello, World!";
-Console.WriteLine(helloworld1);
+// string helloworld1 = "Hello, World!";
+// Console.WriteLine(helloworld1);
 
-String helloworld2 = "Hello, World!";
-Console.WriteLine(helloworld2);
+// String helloworld2 = "Hello, World!";
+// Console.WriteLine(helloworld2);
 
-var helloworld3 = "Hello, World!";
-Console.WriteLine(helloworld3);
+// var helloworld3 = "Hello, World!";
+// Console.WriteLine(helloworld3);
 
-string $helloworld4 = "Hello, World!";
-Console.WriteLine($helloworld3);
+// string $helloworld4 = "Hello, World!";
+// Console.WriteLine($helloworld3);
 
-string helloworld5 = 'Hello, World!';
-Console.WriteLine($helloworld5);
+// string helloworld5 = 'Hello, World!';
+// Console.WriteLine($helloworld5);
 
-var helloworld6;
-helloworld6 = "Hello, World!";
-Console.WriteLine(helloworld6);
\ No newline at end of file
+// var helloworld6;
+// helloworld6 = "Hello, World!";
+// Console.WriteLine(helloworld6);
+
+char a = 'c';
+int b = 10;
+decimal c = 10.2m;
+bool d = false;
+
+var e = 'c'; 
+var f = 10;
+var g = 10.2m;
+var h = true;
+float g = 10.2m;
+
+// Console.WriteLine(a);
\ No newline at end of file