using the cp command in a program in os x

ok i have this program, i want to have it so the user types in the path of a file, and then the programs copies that file to another specified location. i have this so far:

Code:

---


#include <stdio.h>

int main()
{
  char orig[50];
  char dest[50];
     
  printf("where is the file you would like to copy? start with desktop, with a \"/\" between each foler. \n");
  scanf("%s",&orig);
  printf("where would you like this file to be copied to? use the same format \n");
  scanf("%s",&dest);
   
  system("cp ~/%s ~/%s", orig, dest);
   
  printf("DONE!");
   
  return(0);
}

---

the problem is it comes up with an error that says "users/peter/%s isnt a directory"
how do i get it to recognize the string i have after it? or can i at all?

thanks

system doesn't take data specifiers in its argument. You have to strcat the whole thing together and send that to system().

Also, use [CODE] tags.

i thought i did use code tages...oops...and i dont know what strcat is, so either you could explain it briefly? or i can wait
thanks

Code:

---

#include <stdio.h>
#include <string.h>  // For string functions including strcat();

int main() {
  char str1[13] = "Hello ";
  char str2[7] = "World!";

  strcat(str1,str2);    // strcat(a,b) appends b to a.
  printf("%s", str1);

  return 0;
}

/* Output:
  Hello World! */

---

A bit more detail, for you. First off, system(), which by the way is actually in <stdlib.h>, is generally frowned upon. Secondly, scanf() isn't used for strings. Especially strings that may contain spaces. If the input was "C:/Documents And Settings/..." you'd end up with "C:/Documents". You should be using fgets() for strings.

Quote:

---

Originally Posted by SlyMaelstrom

Code:

---

#include <stdio.h>
#include <string.h>  // For string functions including strcat();

int main() {
  char str1[7] = "Hello ";
  char str2[7] = "World!";

  strcat(str1,str2);    // strcat(a,b) appends b to a.
  printf("%s", str1);

  return 0;
}

/* Output:
  Hello World! */

---

---

Hmm?

how would i use that though?

Quote:

---

Originally Posted by Dave_Sinkula

Hmm?

---

Whoops... good call. I'm a boob.

ok im lost....

Boobies.

Code:

---

#include <stdio.h>

int main()
{
  char orig[50];
  char dest[50];
  char stuff[100];
     
  printf("where is the file you would like to copy? start with desktop, with a \"/\" between each foler. \n");
  scanf("%s", orig);
  printf("where would you like this file to be copied to? use the same format \n");
  scanf("%s", dest);

  sprintf(stuff, "cp ~/%s ~/%s", orig, dest);

  system(stuff);
  printf("DONE!");
   
  return(0);
}

---

Also, ~ is interpreted by the shell, not the cp command.

Perform the substitution of ~ in the code itself - ideally passing to the cp command two absolute paths.

woah thanks everyone that helped. i cant try that now, but i will when i get home (school, always getting in the way)
quick question, i asked this question at the ipodlinux forums, and they said the command was snprintf(blah blah) not sprintf(blah blah), which is it?

Well snprintf() is preferable if you have it, but it is a C99 standard function. It is not a C89 function.

It's safer, but you lose some portability (basically)

thanks you guys it worked, i wouldnt have been able to figure that out. thanks a bunch, ill be back!

thanks

Quote:

---

Originally Posted by Dave_Sinkula

Hmm?

---

No, he was correct before. str1 should be a size of 13 to allow Hello World!\0. Read the manual for strcat, char *s MUST be large enough to hold what it is being appended.

question, can you have more than one getchar in a program? cause everytime i have more than one getchar, with an if/else following, the if's and else's get ignored.
here's teh code:

Code:

---

/*
 *  copy.c
 * 
 *
 *  Created by Peter Noone on 4/6/06.
 *  Copyright 2006 __MyCompanyName__. All rights reserved.
 *
 */

#include <stdio.h>

int main()
{
        char q;
        char a;
        char original[50];
        char orig[50];
        char file[10];
        char dest[50];
        char cp[100];
               
        printf("where is the file you would like to copy? \nif the file is on the desktop, type \"y\" \nif not, type \"n\" \n");
        q=getchar();
        if(q=='y')
        {
                printf("now type the file name.\n");
                scanf("%s", &file);
                sprintf(original,"~/desktop");
                sprintf(orig,"desktop/%s",file);
        }
       
        else
        {       
                printf(" type the full path of the file, start with \"/desktop,\" with a \"/\" \n between each foler. \n");
                scanf("%s",&orig);
        }
       
        if(q=='y')
        {
                printf("would you like the copy made to the same location? (y/n)\n");
                a=getchar();
                if(a=='y')
                {
                        sprintf(dest,original);
                }
        }
        else
        {
                printf("where would you like this file to be copied to?\n");
                printf("type the full path of the destination. \n");
                scanf("%s",dest);
        }
       
        sprintf(cp,"cp ~/%s ~/%s", orig, dest);
       
        system(cp);
       
        printf("DONE!");
       
        return(0);
}

---

and here's what i get when i run it (it only works if i chose a file that was on the desktop. i.e. if i chose "y" at the first option)

Code:

---

new-host-2:/users/peter/desktop/other/programming Peter$ ./copy
where is the file you would like to copy?
if the file is on the desktop, type "y"
if not, type "n"
y
now type the file name.
5g.scpt
would you like the copy made to the same location? (y/n)
cp: /Users/Peter/??.?: Invalid argument
DONE!

---

thanks

Quote:

---

Originally Posted by Apocalypse

No, he was correct before. str1 should be a size of 13 to allow Hello World!\0. Read the manual for strcat, char *s MUST be large enough to hold what it is being appended.

---

He was quoting my original code, which I then changed after he pointed out the little typo.

i guess my main question is can you have
a) multiple if statements in a program (im guessin yes)
b) can you have an "if" inside another "if" (not so sure)

any suggestions/answers?

thanks

> can you have more than one getchar in a program?
Yes, yes and yes to your questions.

However, your problem is basically one of mixing getchar() and scanf().
scanf() processes the minimum number of characters necessary to complete your conversion string, and anything else is left for the next input call. This normally isn't a problem if the next call is another scanf call, but for any other input function, the results are surprising.

So, what you would do is something like

Code:

---

int main()
{
  char buff[BUFSIZ];
  char q;
  char a;
  char original[50];
  char orig[50];
  char file[10];
  char dest[50];
  char cp[100];
   
  printf("where is the file you would like to copy? \n"
        "if the file is on the desktop, type \"y\" \n"
        "if not, type \"n\" \n");
  fgets( buff, sizeof buff, stdin );
  q=buff[0]; /* q=getchar(); */
  if(q=='y')
  {
    printf("now type the file name.\n");
    fgets( buff, sizeof buff, stdin );
    sscanf( buff, "%s", file); /* scanf("%s", &file); */

---

ok thanks for the help, but that looks way beyond me (me being about half way through c for dummies) so ill wait. i have a few working versions, just without all the bells and whistes i would like. i made one to try to let the user choose between rm, cp, and mv. needless to say it didnt work...ill just have to wait. thanks a lot

There's an FAQ entry on clearing the input buffer: http://faq.cprogramming.com/cgi-bin/...&id=1043284392

i dont realy get that, or what it does or how it helps...why is my program skipping over the if's and getchar's after the first one?

q=getchar();
You type in 'y' and enter.
The 'y' is read by getchar() and the '\n' is left for the next input function to deal with.

scanf("%s", &file);
You type in "file.txt" and press enter.
But there was a '\n' from the previous input there already. This is OK because scanf(%s) skips leading white space such as newlines, so all you get stored in your variable is "file.txt". The '\n' at the end is left for the next input function to deal with.

a=getchar();
OOPS - you lose.
getchar() just sees the '\n' left behind by the previous scanf() call and throws off your entire program logic.

/me *points to answer using fgets*

ok thanks a lot, i think this was getting a little beyond my skill level haha. but with the help of some guys at ipodlinux forums, it works! thanks a lot you guys,you helped a lot