增加C#第4题

data/1..NET初阶/2.C#语法/3.C#字符串格式设置/Format.json

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

data/1..NET初阶/2.C#语法/3.C#字符串格式设置/Format.md

+# 字符串格式化
+
+C# 提供了丰富的字符串格式化支持。
+
+* 普通字符串可以使用`\`来做转义
+* 支持插入 Unicode 编码
+* 使用 `@"23六jlqkjr"` 风格可以实现逐字文本输出
+* 使用 `$"{variable_name}"` 风格可以在字符串内插入变量
+
+以下格式化代码，能正确运行的有哪些？
+
+一：
+
+```csharp
+Console.WriteLine("{\"err\":\"success\", \"value\":\"C#之父: 安德斯·海尔斯伯格\"}");
+Console.WriteLine("{\"err\":\"success\", \"value\":\"C:\\data\"}");
+```
+
+二：
+
+```csharp
+Console.WriteLine("{\"err\":\"success\", \"value\":\"\u0043\u0023\u4e4b\u7236\u003a\u0020\u5b89\u5fb7\u65af\u00b7\u6d77\u5c14\u65af\u4f2f\u683c\"}");
+```
+
+三：
+
+```csharp
+Console.WriteLine(@"
+{
+    ""err"": ""success"",
+    ""value"": ""C#之父: 安德斯·海尔斯伯格""
+}
+");
+```
+
+四：
+
+```csharp
+var msg = "success";
+var value = "C#之父: 安德斯·海尔斯伯格";
+Console.WriteLine($"{{\"err\":\"{msg}\", \"value\":\"{value}\"}}");
+```
+
+五：
+
+```csharp
+var msg = "success";
+var value = "C#之父: 安德斯·海尔斯伯格";
+Console.WriteLine($@"
+{{
+    ""err"": ""{msg}"",
+    ""value"": ""{value}""
+}}
+");
+```
+
+六：
+
+```csharp
+var msg = "success";
+var value = "C#之父: 安德斯·海尔斯伯格";
+Console.WriteLine($@"
+{
+    "err": "{msg}",
+    "value": "{value}"
+}
+");
+```
+
+七：
+
+```csharp
+var msg = "";
+var value = "";
+Console.WriteLine(@"
+{
+    "err": "success",
+    "value": "C#之父: 安德斯·海尔斯伯格"
+}
+");
+```
+
+## 答案
+
+```bash
+一、二、三、四、五
+```
+
+### 选项
+
+### A
+
+```bash
+一、二、三、四、六
+```
+
+### B
+
+```bash
+一、二、三、五、六
+```
+
+### C
+
+```bash
+二、三、四、五、七
+```
+
+### D
+
+```bash
+一、三、四、五、七
+```

data/1..NET初阶/2.C#语法/3.C#字符串格式设置/config.json

@@ -2,5 +2,7 @@
   "node_id": "csharp-6213732b191f434fb809de14eadee919",
   "keywords": [],
   "children": [],
-  "export": []
+  "export": [
+      "Format.json"
+  ]
 }
\ No newline at end of file

data/1..NET初阶/2.C#语法/3.C#字符串格式设置/sample/Program.cs

+// See https://aka.ms/new-console-template for more information
+Console.WriteLine("Hello, World!");
+
+Console.WriteLine("{\"err\":\"success\", \"value\":\"C#之父: 安德斯·海尔斯伯格\"}");
+Console.WriteLine("{\"err\":\"success\", \"value\":\"C:\\data\"}");
+Console.WriteLine("{\"err\":\"success\", \"value\":\"\u0043\u0023\u4e4b\u7236\u003a\u0020\u5b89\u5fb7\u65af\u00b7\u6d77\u5c14\u65af\u4f2f\u683c\"}");
+Console.WriteLine(@"
+{
+    ""err"": ""success"",
+    ""value"": ""C#之父: 安德斯·海尔斯伯格""
+}
+");
+
+var msg = "success";
+var value = "C#之父: 安德斯·海尔斯伯格";
+Console.WriteLine($"{{\"err\":\"{msg}\", \"value\":\"{value}\"}}");
+
+Console.WriteLine($@"
+{{
+    ""err"": ""{msg}"",
+    ""value"": ""{value}""
+}}
+");
+
+Console.WriteLine($@"
+{{
+    ""err"": ""{msg}"",
+    ""value"": ""{value}""
+}}
+");
\ No newline at end of file

data/1..NET初阶/2.C#语法/3.C#字符串格式设置/sample/sample.csproj

+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <TargetFramework>net6.0</TargetFramework>
+    <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
+  </PropertyGroup>
+
+</Project>