Building new JSON data starts with creating JSON objects and adding them to each other. Different functions from the json-c library create objects and add them to each other, which is how JSON data is built within a C program. The JSON data created can be output as a string, or the string can be saved to a file just as any string is saved to a file in C.
- [Instructor] As with reading JSON data … in the JSON C library, creating JSON data … involves using a JSON object variable. … In this code, a new JSON object, jdata, … is created at line 11. … It's empty. … No other objects are added, still the object exists, … and it can be output which is what happens … at line 20. … The object is converted to a string … and it's output directly to the console. … Now I have already compiled and linked the code … so let's see what it does. … And there's the new object. … Not very helpful, but it was created. … In this update, a second JSON object is created. … The JSON object, jnewobj, is created at line 19, … assigned to the strong George Washington. … At this point, the code has two JSON objects independent … of each other, but at line 30, … the json_object_object_add function … adds the jnewobj string to the jdata object, … assigning it to a keyname, Name. … As before, this object is converted to a string, … and then output. … Let's see what it looks like. …
Author
Dan Gookin
Released
10/1/2019- Finding, installing, and linking libraries
- Accessing and generating XML data
- Working with JSON
- Working with the libcurl library
- Text programming
- Reading, writing, and manipulating JPEG images
- Working with PNG images
Skill Level Advanced
Duration
Views
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Introduction
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Using the exercise files1m 2s
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Working with the code2m 45s
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1. Setup and Configuration
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Understanding libraries2m 50s
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Finding a C library2m 44s
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Installing a library4m 15s
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Liking a library: IDE4m 10s
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2. Data Structures
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Understanding XML2m 23s
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Accessing XML data3m 26s
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Generating XML data3m 57s
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Working with JSON2m 39s
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Accessing JSON data3m 10s
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Reading JSON data3m 46s
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Creating JSON output3m 35s
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3. Web Access
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Testing libcurl2m 3s
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Fetching a web page3m 47s
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Saving web data3m 31s
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Sending data2m 35s
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4. Text Programming
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Working with wide characters3m 19s
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Building an ncurses program2m 27s
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Controlling the text screen2m 32s
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Making color text2m 56s
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Exploring ncurses input4m 6s
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5. Computer Graphics
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Accessing a JPEG2m 31s
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Manipulating JPEG images3m 5s
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Working with PNG images3m 57s
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Modifying a PNG image2m 26s
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Conclusion
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Writing your own library4m 19s
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Next steps1m 17s
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Video: Creating JSON output