Bartman wrote:Please mark multiline code using the suitable tags.
A semicolon is missing at the end of the first \coordinate command.
1st message>> Sorry,what does it means? Sorry I do not good at English... Could you show me a good program code?
2nd message>> oh! thank you! But the result does not change...
Look at the line for coordinate A here, I put the semicolon at the end. It is missing in your original code. Every TikZ path has to end with a semicolon.
You can click on "Run LaTeX here" to see that it works.
By the way, I removed the dvipdfmx option, which is not compatible with LuaLaTeX, required by ltjsarticle.
To 2. you accidentally used the "LaTeX" button, which is for inline code marking of LaTeX commands. For multiple lines of code, there's the "Code" button at the left top of the editor field when writing. Not perfect, I guess. I edited it above.