Using C++ in XCode 4 - .out file?

Discussion in 'Mac Programming' started by ArtOfWarfare, Sep 14, 2011.

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  1. ArtOfWarfare, Sep 14, 2011
    Last edited: Sep 14, 2011

    ArtOfWarfare macrumors G3

    ArtOfWarfare

    Joined:
    Nov 26, 2007
    #1
    Hi, I've already learned C and Obj-C, but I'm taking a class in C++ in school right now. The instructor wants us to send him 3 things:
    1.) The .cpp source code file.
    2.) A screenshot of the output.
    3.) The .out file.

    #1 and 2 are easy enough to get, but I'm confused about #3. What is a .out file and how do I get one in Xcode 4?

    Here's the code, I've highlighted the lines pertaining to making the file in blue.
    Code:
    #include <iostream>
#include <fstream>
#include <iomanip>
using namespace std;
#define HEIGHT 7.0

int main()
{
	[color=BLUE]ofstream outfile; //declare variable to write to file
	outfile.open("hw1.out");[/color]
	double side[2], area, volume;
	side[0] = 2.0;
	side[1] = 3.0;
	area = side[0]*side[1]/2.0;
	volume = area*HEIGHT/3.0;
	cout<<"Side 1 is "<<side[0]<<"cm and side 2 is "<<side[1]<<"cm\n\n";
	cout<<"First pyramid volume is "<<volume<<" cm^3\n\n";
	[color=BLUE]outfile<<"Side 1 is "<<side[0]<<"cm and side 2 is "<<side[1]<<"cm\n\n";
	outfile<<"First pyramid volume is "<<volume<<" cm^3\n\n";[/color]
	cout<<"Enter new lengths for the two sides:\n";
	cin>>side[0]>>side[1];
	area = side[0]*side[1]/2.0;
	volume = area*HEIGHT/3.0;
	cout<<"Second pyramid volume is "<<volume<<" cm^3\n\n";
	cout<<"Side 1 is "<<side[0]<<" cm and side 2 is "<<side[1]<<" cm\n\n";
	cout<<"The volume of the pyramid to six decimals is:\n\n";
	cout<<fixed<<setprecision(6)<<volume<<" cm^3\n\n";
	[color=BLUE]outfile<<"Second pyramid volume is "<<volume<<" cm^3\n\n";
	outfile<<"Side 1 is "<<side[0]<<"cm and side 2 is "<<side[1]<<"cm\n\n";
	outfile<<"The volume of the pyramid to six decimals is:\n\n";
	outfile<<fixed<<setprecision(6)<<volume<<" cm^3\n\n";
	outfile.close();[/color]
	return volume;
}
     
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  2. gnasher729, Sep 14, 2011

    gnasher729 macrumors P6

    gnasher729

    Joined:
    Nov 25, 2005
    #2
    Your program creates a file named hw1.out.

    Use Spotlight to find it.
     
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  3. ArtOfWarfare, Sep 14, 2011

    ArtOfWarfare thread starter macrumors G3

    ArtOfWarfare

    Joined:
    Nov 26, 2007
    #3
    No results are found.

    (That's not quite true. This webpage shows up as a result, as does my .cpp file.)

    Edit: I changed the search to include system files, it found it in...

    <Home> > Library > Developer > Xcode > DerivedData > <Project> > Build > Products > Debug > hw1.out
     
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  4. chown33, Sep 14, 2011

    chown33 macrumors 604

    Joined:
    Aug 9, 2009
    Location:
    Sailing beyond the sunset
    #4
    The same rules apply as for C or Objective-C programs.

    The pathname for your output file is a relative path. It's relative to the current working directory. So if you know the working directory, you know where the file should be. I say "should be" because I don't see any error-checking, and it's possible the output file can't be created or written to. So it's possible that the output file won't exist (or won't be overwritten), even if you know the working directory.

    To find where you set the working directory for an executable running from Xcode, try entering the term into Xcode's help. Or just open the Executable's options window (Xcode < 4) and look carefully in the different tab panes.

    If you don't know what a working directory is, look it up on Wikipedia (along with relative path vs. absolute path).

    Here's a simple C program to print the working directory, pretty much like the 'pwd' command does:
    Code:
    #include <stdio.h>
#include <unistd.h>

// prints working directory
int main()
{
	char buf[ FILENAME_MAX ];

	char * result = getcwd( buf, sizeof( buf ) );
	if ( result )
		printf( "%s\n", result );
	else
		perror( NULL );

	return result == NULL;  // 0 on success, 1 on failure
}
    If you don't know what getcwd() or perror() do, you can look them up in Xcode's API help, too. Or google them, since they're standard Posix C functions.
     
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  5. jiminaus, Sep 14, 2011

    jiminaus macrumors 65816

    jiminaus

    Joined:
    Dec 16, 2010
    Location:
    Sydney
    #5
    For Xcode >=4, you can specify a custom working directory under the options of the run step of the current scheme.
     
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  6. robvas, Sep 14, 2011

    robvas macrumors 68030

    Joined:
    Mar 29, 2009
    Location:
    USA
    #6
    It's easy to do from the terminal as well:

    [​IMG]
     
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  7. ArtOfWarfare, Dec 4, 2011

    ArtOfWarfare thread starter macrumors G3

    ArtOfWarfare

    Joined:
    Nov 26, 2007
    #7
    Just a little update for anyone with a similar problem...

    As of Lion, the libraries for users are hidden by default.

    Not just that, but Spotlight won't find things within the hidden libraries even when "System Files are Included".

    It's really irritating how difficult Apple is making it to actually be a developer starting out. Just make the learning curve steeper and steeper...

    Anyways, open terminal and type

    Code:
    chflags nohidden ~/Library/
    And user libraries will appear again you'll be able to find the files within using Spotlight again (of course, you still need to explicitly say that System Files are Included)
     
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  8. jiminaus, Dec 4, 2011
    Last edited: Dec 4, 2011

    jiminaus macrumors 65816

    jiminaus

    Joined:
    Dec 16, 2010
    Location:
    Sydney
    #8
    It's easier with Xcode 4.2. Go into XCode's preferences, go into the locations section, under the locations tab change Derived Data from Default to Relative. Then you'll have a DerivedData subdirectory inside your project directory. All your build artefacts will be under there.

    For example, after changing the preference, if I create a C command-line project called CmdLineTest in my Documents directory, then the executable is at:

    ~/Documents/CmdLineTest/DerivedData/CmdLineTest/Build/Products/Debug/CmdLineTest


    And alternative technique, which also works in XCode 4.0, is to go into the Organizer. In the projects section, click your project. It will show you the path of that project's derived data directory. Click the arrow on the circle next to that path to reveal the directory in Finder. The executable is in the Build/Products/Debug subdirectory.
     
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