Function main

example/tutorial/tutorial.cpp:11–151

using namespace std;

int main(int, char*[]) {
    ////////////////////////////////////////////////////////////////////////////
    // 1. Parse a JSON text string to a document.

    const char json[] = " { \"hello\" : \"world\", \"t\" : true , \"f\" : false, \"n\": null, \"i\":123, \"pi\": 3.1416, \"a\":[1, 2, 3, 4] } ";
    printf("Original JSON:\n %s\n", json);

    Document document;  // Default template parameter uses UTF8 and MemoryPoolAllocator.

#if 0
    // "normal" parsing, decode strings to new buffers. Can use other input stream via ParseStream().
    if (document.Parse(json).HasParseError())
        return 1;
#else
    // In-situ parsing, decode strings directly in the source string. Source must be string.
    char buffer[sizeof(json)];
    memcpy(buffer, json, sizeof(json));
    if (document.ParseInsitu(buffer).HasParseError())
        return 1;
#endif

    printf("\nParsing to document succeeded.\n");

    ////////////////////////////////////////////////////////////////////////////
    // 2. Access values in document. 

    printf("\nAccess values in document:\n");
    assert(document.IsObject());    // Document is a JSON value represents the root of DOM. Root can be either an object or array.

    assert(document.HasMember("hello"));
    assert(document["hello"].IsString());
    printf("hello = %s\n", document["hello"].GetString());

    // Since version 0.2, you can use single lookup to check the existing of member and its value:
    Value::MemberIterator hello = document.FindMember("hello");
    assert(hello != document.MemberEnd());
    assert(hello->value.IsString());
    assert(strcmp("world", hello->value.GetString()) == 0);
    (void)hello;

    assert(document["t"].IsBool());     // JSON true/false are bool. Can also uses more specific function IsTrue().
    printf("t = %s\n", document["t"].GetBool() ? "true" : "false");

    assert(document["f"].IsBool());
    printf("f = %s\n", document["f"].GetBool() ? "true" : "false");

    printf("n = %s\n", document["n"].IsNull() ? "null" : "?");

    assert(document["i"].IsNumber());   // Number is a JSON type, but C++ needs more specific type.
    assert(document["i"].IsInt());      // In this case, IsUint()/IsInt64()/IsUInt64() also return true.
    printf("i = %d\n", document["i"].GetInt()); // Alternative (int)document["i"]

    assert(document["pi"].IsNumber());
    assert(document["pi"].IsDouble());
    printf("pi = %g\n", document["pi"].GetDouble());

    {
        const Value& a = document["a"]; // Using a reference for consecutive access is handy and faster.