strcpy problem

utkarshrawat · 07-01-2010, 03:26 AM

I am getting Segmentation fault error .Dont know where it is

Code:

#include <unistd.h>

#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <sys/socket.h>
#include <netinet/in.h>
main()
{
	uint8_t ip[4];
	strcpy(ip[0],"192");	
	printf("%s",ip[0]);
}
Getting Segmentation fault

Aquarius_Girl · 07-01-2010, 03:32 AM

The changes have been marked in red.

Code:

#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <sys/socket.h>
#include <netinet/in.h>
main()
{
  uint8_t ip[4];
  strcpy(ip, "192");
  printf("%c",ip[0]);
}

Aquarius_Girl · 07-01-2010, 03:34 AM

Do read the following link completely, PLEASE
http://www.unknownroad.com/rtfm/gdbtut/gdbtoc.html

grail · 07-01-2010, 03:36 AM

Well upon a quick search on google, most links seem to say that the definition for uint8_t come from stdint.h which you don't seem to have included.
Not a 100% sure but this would be a good place to start.

Aquarius_Girl · 07-01-2010, 03:58 AM

At least read this one:
http://www.unknownroad.com/rtfm/gdbtut/gdbsegfault.html

johnsfine · 07-01-2010, 05:44 AM

The changes anishakaul suggested should fix the seg fault that the original code hits as well as the next seg fault it would hit if just the first were corrected. But the second correction probably doesn't fit the original intention of the code. I think the second correction should be the same as the first:

Code:

	printf("%s",ip);

ip (when passed as a parameter to a function) is the address of element zero of the array ip[]. The address of element zero is the same address and in this example the same type as the address of the array itself.

ip[0] is the value of element zero.

Those two function calls each need an address for the parameter for which the OP passed ip[0].

Aquarius_Girl · 07-01-2010, 05:52 AM

Quote:

Originally Posted by johnsfine

I think the second correction should be the same as the first:

Code:

	printf("%s",ip);

You are right, i tested it just now.

Sergei Steshenko · 07-01-2010, 06:14 AM

Such problems are immediately caught at compilation stage by '-Wall- Wextra -Wformat=2'.

utkarshrawat · 07-02-2010, 07:56 AM

Thanks to all for the reply .It came
Now I want an IP(Internet Protocol) should be stored in uint_t ip[3];
ip[0]=192;
ip[1]=168;
ip[2]=1;
ip[3]=123;

output should come like this 192.168.1.123,with the (.)dot

johnsfine · 07-02-2010, 08:00 AM

Quote:

Originally Posted by utkarshrawat

Now I want an IP(Internet Protocol) should be stored in uint_t ip[3];
ip[0]=192;
ip[1]=168;
ip[2]=1;
ip[3]=123;

output should come like this 192.168.1.123,with the (.)dot

You better make that uint_t ip[4] because declaring 3 only lets you use 0..2.

Beyond that, you seem to be asking us to write your code for you.

If this is homework, you shouldn't ask that and others replying shouldn't do it.

Even if it isn't homework, please make some real effort at doing your own work.

smeezekitty · 07-02-2010, 01:46 PM

uint_t ip[4][4] ?

MTK358 · 07-05-2010, 11:14 AM

int ip[4];

AFAIK he wants the individual elements to be integers, not strings.