how to store results of ./a.out to a text file

Question

I am wondering if there is any way to store the results of my program into a text file. I know you can just do something like ./a.out > output.txt but for my program, after I type ./a.out I am prompted again for TIME: where I put in the amount of time, and then upon hitting enter the algorithm is performed and the results are output.

The program outputs a stage for a period of time, and basically my output looks like this:

time 0:00 stage 1

time 0:05 stage 1

...

time 2:05 stage 2

How can I get the output stored into a text file?

Answer 1

So redirect the input as well:

./a.out < input.txt > output.txt

Where input.txt contains the amount of time.

Answer 2

One way to do it is to print the result to stderr

fprintf(stderr, "time %d:....");

And redirect stderr to output.txt

./myprog 2> output.txt

Note: this is a workaround if you don't wish to open a file, I don't like using stderr for anything other than errors.

Answer 3

一种解决方案是将TIME参数作为参数传递，并使用./a.out time> output.txt将其输出到文件。

Answer 4

The simplest method is what sudo_O told you (it works in every os)

./a.out <in.txt >out.txt. 

If you want to do this in C, use freopen() ( http://www.cplusplus.com/reference/clibrary/cstdio/freopen/ )

 freopen ("myoutput.txt","w",stdout);
 freopen ("myinput.txt","r",stdin);

This redirects stdout to myoutput.txt, so all printfs goes to "myoutput.txt". Also redirects stdin to myinput.txt, so all scanfs are reading from "myinput.txt".