Xcode & passing command line arguments

Question

I just started working with C & Xcode and I've run into a little difficulty.

All I want to do is read a file from the command line and see the output in the terminal. I think my problem lies with the path to the file that I want to read in. I'm using a Mac and the file is on my desktop, so the path should be Users/myName/Desktop/words.txt. Is this correct?

This is my code:

#import <Foundation/Foundation.h>

int main (int argc, const char* argv[]){

    if(argc == 1){
        NSLog(@" you must pass at least one arguement");
        return 1;
    }
    NSLog(@"russ");
    FILE*  wordFile = fopen(argv[1] , "r");
    char word[100];

    while (fgets(word,100,wordFile)) {

        NSLog(@" %s is %d chars long", word,strlen(word));

    }

    fclose(wordFile);
    return 0;

}//main

Answer 1

Close... it's

/{Volume}/Users/myName/Desktop/words.txt

... where {Volume} is the name of your hard drive. You can also try using:

~/Desktop/words.txt

... where ~ is understood to mean "your home directory", but this might not resolve correctly.

Answer 2

The path to the desktop is /Users/[username]/Desktop/

~/Desktop/ is a user-agnostic way of denoting this, ~ represents the current users home directory. It must be expanded using a method like stringByExpandingTildeInPath

Not sure about using C# (I've never used it on Mac OS X), but in Objective-C/Cocoa, you would do..

// Get array with first index being path to desktop
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDesktopDirectory, NSUserDomainMask, YES);

// Get the first element
NSString *desktopPath = [paths objectAtIndex:0];

// Append words.txt to path
NSString *theFilePath = [desktopPath stringByAppendingPathComponent:@"words.txt"];

NSLog(@"%@", theFilePath);

This is the most robust way of getting the Desktop path, as a user could technically move their Desktop folder else where (although this is pretty unlikely). Another valid option is to use the NSString method stringByExpandingTildeInPath:

NSString *desktop = [@"~/Desktop" stringByExpandingTildeInPath];
NSString *theFile = [desktop stringByAppendingPathComponent:@"words.txt"]

As I said, both those are in Objective-C, but it shouldn't be hard to translate to C#, assuming you can get at the Cocoa libraries.

---

The code you posted works correctly:

dbr:.../build/Debug $ ./yourcode ~/Desktop/words.txt 
yourcode[2106:903] russ
yourcode[2106:903]  this is words.txt is 17 chars long

Your terminal automatically expands the ~/ tilda path

Answer 3

(Note - this appears to be a C question, not a C# question)

Actually, you can do:

/Users/myName/Desktop/words.txt

You don't have to give the path to the volume.

However, to get the full path in C you'd do something like:

#include <stdlib.h>
#include <stdio.h>
#include <string.h>
char *home, *fullPath;

home = getenv("HOME");

fullPath = strcat(home, "/Desktop/words.txt");

The issue you're running into with passing the filename as an argument is that you need to set the current working directory to the place where the file exists.

Answer 4

If you need the path to a file in OS X, an easy way to get it is to just drag the file into the Terminal.app window where you are typing the command. Voila!