[latex] error type summary (hold the change)

Excellent related blog posts show the way ：
《latex A brief analysis of common error prompts and causes 》

undefined

1. Undefined control sequence. ...can be paid by the site, when $P_w<\vertp
   Error message prompt ：
   
   Chestnut one ：markdown Syntax error in
   
   correct :\vertp-->\vert Wrong command .
   That is, there latex A command unknown to the compiler exists , So the display is undefined .
   Chestnut two ：latex Syntax error in
   

Package

1. Package inputenc Error: Unicode character . (U+3002)(inputenc) not set up for use with LaTeX. ... task cost, i.e. $|p_ j|-C_ {kj}(x,a)$.
   
   reason ： Chinese punctuation marks appear .
   Chestnut one ： comma
   
   Chestnut two ： Full stop
   
   Chestnut three ： Single quotation marks
   
   Chestnut three ： Chinese characters appear ( stay .bib In file )

Look at the original

2. Package amsmath Error: Multiple \label's: label 'Eq.12' will be lost. \end{align}
   
   Look at the original
   
   reason ： Label write multiple times , Report errors

Unknow

1. Unknown float option `q’. \begin{table}[htbq]
   
   reason ： Unknown option appears q. modify ：q–>p
   

Illegal

1. Illegal character in array arg. \begin{tabular}{c|c|C|C|C}
   
   reason ： There are unreasonable characters . Obviously here c Misspelled as C, And report wrong