Still celebrating National IT Professionals Day with 3 months of free Premium Membership. Use Code ITDAY17

x
?
Solved

Reading a filename from command line.

Posted on 2003-10-25
4
Medium Priority
?
246 Views
Last Modified: 2010-04-01
I was wondering what is the correct way to read a filename from the command line?
Note: Not by prompting for and reading in a string.

Thanks
0
Comment
Question by:killer455
[X]
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
4 Comments
 
LVL 1

Accepted Solution

by:
marcin1 earned 80 total points
ID: 9621488
Here is the example how to handle arguments from the command line:

#include <string.h>
int main(int argc, char* argv[])
{
        if (argc > 1)
        {
                //here you can use filename
                printf("argument 1: %s", argv[1]);
        }
        return 0;
}

argc - number of arguments (including the name of the program)
argv - array containing the arguments

argv[0] is the name of your program

Now try to compile it and run with parameters
0
 
LVL 9

Expert Comment

by:tinchos
ID: 9621507
It can be done in the same way as in C


Your main function should look like this:

int main(int argc, char** argv)
{
   /* Use argc and argv as needed */
}

argc contains the number of command lines arguments + 1 (the first argument is the name of your executable).
argv is an array of strings (char pointers) - each string is a command line argument.

Suppose you call "Program.exe filename.txt"

argc = 2
argv[0] is "program.exe"
argv[1] is "filename.txt"
0
 
LVL 4

Expert Comment

by:n_fortynine
ID: 9621508
For example, if your executable is a.out
$ a.out infile.txt
then argv[0] would contain the executable name (possibly including path - but this is not certain)
and argv[1] is the char array "infile.txt"
so basically if you want to open this file:
ifstream in(argv[1]);
is what you can write (or call the open() function).

Notice that if you have included the path in the file name, all backslashes must be doubled:
Not A:\MyFolder\infile.txt but A:\\MyFolder\\infile.txt
(since the compiler will confuse \M and \i as predefined tags (like \n, \t etc.)

In MS-DOS, the symbol used is "/" so you wouldn't have to worry about that.
0
 

Author Comment

by:killer455
ID: 9624276
Thanks for the help guys.  I guess you cant split only 20 points? i didnt see the "split" button.  Well look for more questions, i got a big (in my rookie opinion) project im working on.  :)

0

Featured Post

Concerto's Cloud Advisory Services

Want to avoid the missteps to gaining all the benefits of the cloud? Learn more about the different assessment options from our Cloud Advisory team.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

What is C++ STL?: STL stands for Standard Template Library and is a part of standard C++ libraries. It contains many useful data structures (containers) and algorithms, which can spare you a lot of the time. Today we will look at the STL Vector. …
Introduction This article is a continuation of the C/C++ Visual Studio Express debugger series. Part 1 provided a quick start guide in using the debugger. Part 2 focused on additional topics in breakpoints. As your assignments become a little more …
The goal of the tutorial is to teach the user how to use functions in C++. The video will cover how to define functions, how to call functions and how to create functions prototypes. Microsoft Visual C++ 2010 Express will be used as a text editor an…
The goal of the video will be to teach the user the difference and consequence of passing data by value vs passing data by reference in C++. An example of passing data by value as well as an example of passing data by reference will be be given. Bot…

688 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question