Program gives error on Ubuntu but runs fine on Windows

[Ihtisham]

Hey guys, when i run the following code on ubuntu(code::blocks) it gives me a number of errors but when i run it on windows(code::blocks) it works fine.

#include <iostream>

using namespace std;

struct link
{
     int data;
     link *next;
};

class linklist
{
     private:
          link *first;
     public:
          linklist()
          {
               first=NULL;
          }
          void display();
          void additem(int d);
};

void linklist:: display()
{
     link *current=first;
     while(current!=NULL)
     {
          cout << current->data << endl;
          current=current->next;
     }
}

void linklist:: additem(int d)
{
     link *current = new link();
     current->data = d;
     current->next = first;
     first = current;
}

int main()
{
     linklist a ;
     a.additem(5);
     a.display();
     return 0;
}

Thanks.

[binarybob350]

What are the errors? My ESP is not working today.

[Ihtisham]

here are the errors:

line14 error:ISO C++ forbids declaration of 'link' with no type

line14 error: expected ';' before '*' token

line18 error: 'first' was not declared in this scope

line26 error: 'current' was not declared in this scope

line26 error: 'first' was not declared in this scope

line36 error: 'current' was not declared in this scope

line36 error: expected type-specifier before 'link'

line36 error: expected ';' before 'link'

line36 error: 'first' was not declared in this scope

[writetonsharma]

you have to put a struct with each declaration ithink.

like

struct link *first;

[writetonsharma]

or you can do this:

typedef struct link
{
     int data;
     link *next;
}link;

[Disch]

I don't really believe he's getting those errors with that code. What he posted is valid C++ and those errors are nonsense.

the whole typedef'ing the struct thing would be a solution for C, but since this is clearly C++ it shouldn't make a difference.

I suspect he's not compiling the code he thinks he is. Maybe there are subtle differences between what he compiled on Windows and what he compiled on Ubuntu.

[Ihtisham]

@Disch: yup, these are non sense but i am getting the errors even if compile the exactly same program from the terminal, and have done it a number of times.

[kempofighter]

Ihtisham wrote:

@Disch: yup, these are non sense but i am getting the errors even if compile the exactly same program from the terminal, and have done it a number of times.

Are you compiling exactly what you posted "here" with both compilers and getting those errors?

[Ihtisham]

Yes, the same i have posted here.

[writetonsharma]

yes.. these will come for C. And he must be compiling for C but looks c++.

on windows if the file is .cpp, it will compile fine. What about ubuntu? could you give the compile command you are using? are you sure you are including iostream?

[Ihtisham]

The file is .cpp in both the places, and using the usual command gcc -o linklist linklist.cpp .

[acorn]

what happens if you put this then run on g++ im just guessing btw so dont yell at me how stupid it is.

#include <iostream>

using namespace std;

struct link; // add this. allow to see declaration of link before link *next is used

struct link
{
     int data;
     link *next;
};

[anonymous23323124]

Correct me if I'm wrong, but shouldn't you be using g++ and not gcc to compile C++ code?

[acorn]

you are right it and i think he is. that was just my error and confusion of the two

[writetonsharma]

classic!!

[z05DSL3A]

You have a name clash. Rename link or put it in a namespace.

[Ihtisham]

Finally it worked thanks alot Grey Wolf, and hey can you explain why there was a clash in ubuntu not in windows?

@Xander314: Yes, you are right g++ should be used because it links to the standard C++ library, but sometimes gcc also works. ;)

[z05DSL3A]

Ihtisham wrote:

can you explain why there was a clash in ubuntu not in windows?

There is a *nix API call called link (for creating hard links in the file system) that is not there on windows.