Arguments to main in C

c command-line-arguments main-method
Anthony picture Anthony · Nov 14, 2010 · Viewed 223.1k times · Source

I don't know what to do! I have a great understanding of C basics. Structures, file IO, strings, etc. Everything but CLA. For some reason I cant grasp the concept. Any suggestions, help, or advice. PS I am a linux user

Answer

cdhowie picture cdhowie · Nov 14, 2010

The signature of main is:

int main(int argc, char **argv);

argc refers to the number of command line arguments passed in, which includes the actual name of the program, as invoked by the user. argv contains the actual arguments, starting with index 1. Index 0 is the program name.

So, if you ran your program like this:

./program hello world

Then:

  • argc would be 3.
  • argv[0] would be "./program".
  • argv[1] would be "hello".
  • argv[2] would be "world".

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