How Can You Redirect scanf to Read from a File in GCC?

[Werg22]

I have a code which uses scanf. How do I make the compiled code read from a (text) file instead from user's input?

 

[mgb_phys]

open the file with fopen() and then use fscanf()
if you search for these terms you should find lots of examples

 

[Werg22]

That's an idea, but I need to be able to do it from the command line... I know there's a way, involving the symbol "<", I just don't remember the details.

 

[mgb_phys]

If you just want the same code to read from a file you can just use:
program << file.txt

 

[Werg22]

Thank you very much. Maybe you can answer this question too: how can I write test cases for my program, keeping in mind it has to read from files? I'm used to using "assert" for tests, by copying my program into a header file and then writing a main function with a bunch of assert statements. In this case, I can't exactly use assert. Is there a statement that opens a file and let's scanf read from it?

 

[D H]

Did you read the second post?