Golang : flag provided but not defined error

Problem :

Your program uses flag.Parse() function to parse the command line arguments and everything is working fine until you attempted to parse a negative value, For example, such as calculating quadratic equation.

./program -3.0 1.0

This will cause the flag.Parse() function to recognize it a flag parameter instead of negative value. How to fix this?

Solution :

Use os.Args instead of flag.Parse. For example, change

 arg := flag.Arg(0)


 arg := os.Args[1]

Happy coding and hope this helps!

  See also : Golang : Get command line arguments

Tags : golang flag-provided parse-flag

Adam Ng By Adam Ng

Get in touch at Google Plus or stay updated on Facebook.

IF you gain some knowledge or the information here solved your programming problem. Please consider donating to the less fortunate or some charities that you like. Apart from donation, planting trees, volunteering or reducing your carbon footprint will be great too.