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# nlohmann::json_sax::number_integer

    virtual bool number_integer(number_integer_t val) = 0;

An integer number was read.

## Parameters

`val` (in)
  integer value

## Return value

Whether parsing should proceed.

## Examples

Example

.The example below shows how the SAX interface is used.

    #include <iostream>
    #include <iomanip>
    #include <sstream>
    #include <nlohmann/json.hpp>

    using json = nlohmann::json;

    // a simple event consumer that collects string representations of the passed
    // values; note inheriting from json::json_sax_t is not required, but can
    // help not to forget a required function
    class sax_event_consumer : public json::json_sax_t
    {
      public:
        std::vector<std::string> events;

        bool null() override
        {
            events.push_back("null()");
            return true;
        }

        bool boolean(bool val) override
        {
            events.push_back("boolean(val=" + std::string(val ? "true" : "false") + ")");
            return true;
        }

        bool number_integer(number_integer_t val) override
        {
            events.push_back("number_integer(val=" + std::to_string(val) + ")");
            return true;
        }

        bool number_unsigned(number_unsigned_t val) override
        {
            events.push_back("number_unsigned(val=" + std::to_string(val) + ")");
            return true;
        }

        bool number_float(number_float_t val, const string_t& s) override
        {
            events.push_back("number_float(val=" + std::to_string(val) + ", s=" + s + ")");
            return true;
        }

        bool string(string_t& val) override
        {
            events.push_back("string(val=" + val + ")");
            return true;
        }

        bool start_object(std::size_t elements) override
        {
            events.push_back("start_object(elements=" + std::to_string(elements) + ")");
            return true;
        }

        bool end_object() override
        {
            events.push_back("end_object()");
            return true;
        }

        bool start_array(std::size_t elements) override
        {
            events.push_back("start_array(elements=" + std::to_string(elements) + ")");
            return true;
        }

        bool end_array() override
        {
            events.push_back("end_array()");
            return true;
        }

        bool key(string_t& val) override
        {
            events.push_back("key(val=" + val + ")");
            return true;
        }

        bool binary(json::binary_t& val) override
        {
            events.push_back("binary(val=[...])");
            return true;
        }

        bool parse_error(std::size_t position, const std::string& last_token, const json::exception& ex) override
        {
            events.push_back("parse_error(position=" + std::to_string(position) + ", last_token=" + last_token + ",\n            ex=" + std::string(ex.what()) + ")");
            return false;
        }
    };

    int main()
    {
        // a JSON text
        auto text = R"(
        {
            "Image": {
                "Width":  800,
                "Height": 600,
                "Title":  "View from 15th Floor",
                "Thumbnail": {
                    "Url":    "http://www.example.com/image/481989943",
                    "Height": 125,
                    "Width":  100
                },
                "Animated" : false,
                "IDs": [116, 943, 234, -38793],
                "DeletionDate": null,
                "Distance": 12.723374634
            }
        }]
        )";

        // create a SAX event consumer object
        sax_event_consumer sec;

        // parse JSON
        bool result = json::sax_parse(text, &sec);

        // output the recorded events
        for (auto& event : sec.events)
        {
            std::cout << event << "\n";
        }

        // output the result of sax_parse
        std::cout << "\nresult: " << std::boolalpha << result << std::endl;
    }

Output:

    start_object(elements=18446744073709551615)
    key(val=Image)
    start_object(elements=18446744073709551615)
    key(val=Width)
    number_unsigned(val=800)
    key(val=Height)
    number_unsigned(val=600)
    key(val=Title)
    string(val=View from 15th Floor)
    key(val=Thumbnail)
    start_object(elements=18446744073709551615)
    key(val=Url)
    string(val=http://www.example.com/image/481989943)
    key(val=Height)
    number_unsigned(val=125)
    key(val=Width)
    number_unsigned(val=100)
    end_object()
    key(val=Animated)
    boolean(val=false)
    key(val=IDs)
    start_array(elements=18446744073709551615)
    number_unsigned(val=116)
    number_unsigned(val=943)
    number_unsigned(val=234)
    number_integer(val=-38793)
    end_array()
    key(val=DeletionDate)
    null()
    key(val=Distance)
    number_float(val=12.723375, s=12.723374634)
    end_object()
    end_object()
    parse_error(position=460, last_token=12.723374634<U+000A>        }<U+000A>    }],
                ex=[json.exception.parse_error.101] parse error at line 17, column 6: syntax error while parsing value - unexpected ']'; expected end of input)

    result: false

## Version history

- Added in version 3.2.0.

Last update: May 17, 2022
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