JSON to C++ Struct Converter

JSON to C++ Struct: Core Features and Principles

Manually writing C++ data structures for complex JSON data is time-consuming and error-prone. This tool automatically generates the corresponding C++ struct or class definition code by parsing your input JSON string based on its key-value pairs and nested relationships. JSON is a lightweight data-interchange format, while C++ structs are composite data types used to organize related data. The core function of this tool is to map JSON objects to C++ structs, map JSON arrays to std::vector<T>, and intelligently infer the types of member variables.

Why Choose Our JSON to C++ Struct Tool?

• Accurate Type Mapping: Intelligently identifies JSON types such as String, Number, Boolean, Array, and Object, accurately mapping them to std::string, int/double, bool, std::vector, and nested structs.
• Ready-to-Use Code: The generated code includes necessary header file includes (e.g., <string>, <vector>) and follows C++ naming conventions, ready to be copied directly into your project.
• Instant Feedback and Validation: Generates C++ code in real-time as you input JSON, supporting format validation to help you quickly verify the rationality of your data structure design.

How to Use

1. Paste or type a properly formatted JSON string into the tool's input box.
2. The tool will automatically parse it and generate the corresponding C++ struct definition code.
3. Review the type mappings in the output code (e.g., number types, array types) to ensure they meet your expectations.
4. Copy the complete generated C++ code snippet and use it directly in your project development.

Frequently Asked Questions (FAQ)

Q: Can the JSON to C++ tool handle null values?
A: They are typically mapped to the default value of the corresponding type or generated as a std::optional type. For example, a null in JSON might appear on the C++ side as an uninitialized int or an empty std::optional<std::string>.

Q: Can this tool generate JSON parsing code?
A: No. This tool only generates the "skeleton" of the data structure (class/struct definitions) and does not include runtime functionality to parse JSON strings or serialize C++ objects. You will need to use third-party libraries like RapidJSON or nlohmann/json to handle the actual data binding and conversion.

Important Notes

Please ensure your input JSON format is valid (you can use an online JSON validator to check it beforehand). The type mappings generated by the tool (such as whether a JSON number is mapped to an int or a double) are based on general rules; for extremely large integers or high-precision floating-point numbers, please adjust them manually. The generated member variable names are converted from JSON keys, so please verify that they comply with your project's naming conventions (e.g., camelCase).

Technical Notes & Best Practices

For C++ backend projects interacting with RESTful APIs, this tool can significantly simplify the definition of data contracts. A typical use case is converting a sample JSON response from API documentation directly into a C++ model, and then using the from_json/to_json functions of the nlohmann/json library for deserialization/serialization. For instance, when processing a response from a user list API, the tool can quickly generate a top-level struct containing a std::vector<User>, saving you the time of manually writing the type for each field. We recommend adding constructors, getters/setters, or serialization methods to the generated code based on your business requirements.