c++ - 将 json 代码格式化为 std::string

Question

这是一个初学者问题，我如何将以下 json 字符串数组格式化为 std::string

[
  { 
    "x" : 12.1,
    "y" : 12.1,
    "z" : 12.1
  },
  { 
    "x" : 12.1,
    "y" : 12.1,
    "z" : 12.1
  },  
  { 
    "x" : 12.1,
    "y" : 12.1,
    "z" : 12.1
  },  
  { 
    "x" : 12.1,
    "y" : 12.1,
    "z" : 12.1
  }
]

这里是json字符串

const std::string json =
            "[\n"
            "  {\n"
            "    \"x\" : 0,\n"
            "    \"y\" : 0,\n"
            "    \"z\" : 0\n"
            "  },\n"
            "  {\n"
            "    \"x\" : 640,\n"
            "    \"y\" : 0,\n"
            "    \"z\" : 0\n"
            "  },\n"
            "  {\n"
            "    \"x\" : 640,\n"
            "    \"y\" : 0,\n"
            "    \"z\" : 480\n"
            "  },\n"
            "  {\n"
            "    \"x\" : 0,\n"
            "    \"y\" : 0,\n"
            "    \"z\" : 480\n"
            "  }\n"
            "]\n";


        Json::Value coordinates;
        Json::Reader reader;

        reader.parse( json, coordinates );

所以我试图解析上面的 json 数组，以获取坐标列表，但无法正确解析。

Answer 1

从 C++11 开始，您可能会使用原始字符串:

const std::string json = R"(
[
  { 
    "x" : 12.1,
    "y" : 12.1,
    "z" : 12.1
  },
  { 
    "x" : 12.1,
    "y" : 12.1,
    "z" : 12.1
  },  
  { 
    "x" : 12.1,
    "y" : 12.1,
    "z" : 12.1
  },  
  { 
    "x" : 12.1,
    "y" : 12.1,
    "z" : 12.1
  }
]
)";

之前，你必须做一些转义，如 " -> \":

const std::string json = 
"[\n"
"  {\n"
"    \"x\" : 12.1,\n"
"    \"y\" : 12.1,\n"
"    \"z\" : 12.1\n"
"  },\n"
"  {\n"
"    \"x\" : 12.1,\n"
"    \"y\" : 12.1,\n"
"    \"z\" : 12.1\n"
"  },\n" 
"  {\n"
"    \"x\" : 12.1,\n"
"    \"y\" : 12.1,\n"
"    \"z\" : 12.1\n"
"  },\n"
"  {\n"
"    \"x\" : 12.1,\n"
"    \"y\" : 12.1,\n"
"    \"z\" : 12.1\n"
"  }\n"
"]\n";