Solved

Reading a filename from command line.

Posted on 2003-10-25
4
239 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
4 Comments
 
LVL 1

Accepted Solution

by:
marcin1 earned 20 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

Is Your Active Directory as Secure as You Think?

More than 75% of all records are compromised because of the loss or theft of a privileged credential. Experts have been exploring Active Directory infrastructure to identify key threats and establish best practices for keeping data safe. Attend this month’s webinar to learn more.

Question has a verified solution.

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

Suggested Solutions

Title # Comments Views Activity
cb: unreferenced local variable 11 72
Lambda for random numbers problem 7 106
Should CArray be used for a list of pointers in C++? 19 97
Dynamically allocate memory 9 55
Introduction This article is the first in a series of articles about the C/C++ Visual Studio Express debugger.  It provides a quick start guide in using the debugger. Part 2 focuses on additional topics in breakpoints.  Lastly, Part 3 focuses on th…
C++ Properties One feature missing from standard C++ that you will find in many other Object Oriented Programming languages is something called a Property (http://www.experts-exchange.com/Programming/Languages/CPP/A_3912-Object-Properties-in-C.ht…
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…
The viewer will learn how to user default arguments when defining functions. This method of defining functions will be contrasted with the non-default-argument of defining functions.

929 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

Need Help in Real-Time?

Connect with top rated Experts

10 Experts available now in Live!

Get 1:1 Help Now