C++

Check if Integer Exists at JSON Path

Demonstrates how to get an integer value at a JSON path, and how to check to see if it exists. C++

#include <CkJsonObject.h>

void ChilkatSample(void)
    {
    bool success = false;

    CkJsonObject json;

    //  First build simple JSON..
    json.UpdateInt("test.abc",100);

    json.put_EmitCompact(false);
    std::cout << json.emit() << "\r\n";

    //  This is our JSON:
    //  {
    //    "test": {
    //      "abc": 100,
    //    }
    //  }

    const char *path = "test.notHere";

    //  The call to IntOf will return 0, because it's not present.
    //  But how do we know if it really was present, and the value was truly 0?
    int val = json.IntOf(path);
    std::cout << "val = " << val << "\r\n";

    //  We cannot use LastMethodSuccess because LastMethodSuccess only applies
    //  to methods that:
    //  - return a string
    //  - return a new Chilkat object, binary bytes, or a date/time.
    //  - returns a boolean status where true = success and false = failed.
    //  - returns an integer where failure is defined by a return value less than zero.
    //  The IntOf method fits none of these requirements, and therefore the LastMethodSuccess 
    //  is not a valid indicator..
    bool wasFound = json.get_LastMethodSuccess();
    std::cout << "wasFound = " << wasFound << " (not a valid indicator)" << "\r\n";

    //  Instead, if the returned value is 0, we can double-check to see if the member was truly there..
    if (val == 0) {
        wasFound = json.HasMember(path);
        std::cout << "wasFound = " << wasFound << "\r\n";
        if (wasFound == true) {
            std::cout << "The value was present and is 0." << "\r\n";
        }
        else {
            std::cout << "no member is present at test.notHere" << "\r\n";
        }

    }
    else {
        std::cout << "val = " << val << "\r\n";
    }

    //  Alternatively, you could check to see if the member exists beforehand..
    if (json.HasMember(path) == true) {
        std::cout << "val = " << json.IntOf(path) << "\r\n";
    }
    else {
        std::cout << "no member at " << path << "\r\n";
    }
    }