Why is regex always true or always false

Question

I am trying to use a regex to determine if a provided file has the .csv extension.

#include 
#include 

int match(const char *strin         


        

Answer 1

The regex you are using is not valid for the regex flavor: the hyphen must be used at the start/end of the bracket expression. Also, you need to escape the dot, else, it will match any char.

Use

const char *reg = "^[a-zA-Z0-9_-]+\\.csv$";

See the C demo.