Same program behaving differently on windows and Linux

Question

The program is for Linked List using Template.

 #include<iostream>
using namespace std;
template <class T>
class link
{

   struct node
   {
          T data;
          struct node * next;
   }*p;
public:
   link();
   void addatbeg(T);
   void show();
   void rematbeg();
   void addatmid(T,T);
};
template <class T>
link<T>::link()
{
 p=NULL;
}
template <class T>
void link<T>::show()
{
 node*q=p;
     while(q->next!=NULL)
{
                    cout<<q->data;
                    cout<<"->";
                    q=q->next;
}
cout<<q->data<<"\n";
}
template <class T>
void link<T>::addatbeg(T a)
{
 node *temp;
 temp=(node*)malloc(sizeof(node));
 temp->data=a;
 temp->next=NULL;
 if(p==NULL)
 {
            p=temp;
 }
 else
 {
            temp->next=p;
            p=temp;
 }
 }
 template <class T>
 void link<T>::rematbeg()
 {
 if(p==NULL)
 cout<<"Link List is Empty\n";
 else
 p=p->next;
 }
 template <class T>
 void link<T>::addatmid(T a,T b)
 {
 node* temp,*q;
 temp=(node*)malloc(sizeof(node));
 temp->data=b;
 temp->next=NULL;
 q=p;
 if(p==NULL)
 cout<<"\n Link List is Empty\n"<<endl;
 else
 {
     while(q->data!=a)
     q=q->next;
 }
 temp->next=q->next;
 q->next=temp;    
 }
 int main()
 {
 link<int> l1;
 l1.addatbeg(2);
 l1.addatbeg(3);
 l1.addatbeg(4);
 l1.addatbeg(5);
 l1.addatmid(3,9);
 l1.show();
 l1.rematbeg();
 l1.show();
 }

The same program runs fine on windows 7 dev C++ compiler while on linux g++ compiler it is giving following errors.

 pllab52.cpp:4:7: error: ‘template<class T> struct link’ redeclared as different kind of symbol
 /usr/include/unistd.h:809:12: error: previous declaration of ‘int link(const char*, const char*)’
 pllab52.cpp:20:1: error: ‘link’ does not name a type
 pllab52.cpp:25:10: error: expected initializer before ‘<’ token
 pllab52.cpp:37:10: error: expected initializer before ‘<’ token
 pllab52.cpp:54:10: error: expected initializer before ‘<’ token
 pllab52.cpp:62:10: error: expected initializer before ‘<’ token
 pllab52.cpp: In function ‘int main()’:
 pllab52.cpp:81:10: error: expected primary-expression before ‘int’
 pllab52.cpp:81:10: error: expected ‘;’ before ‘int’
 pllab52.cpp:82:5: error: ‘l1’ was not declared in this scope

Both C++ program behaving differently. Is it because of both having different compiler or what? Please also tell the solution to solve this problem. Please explain when these kind of problems normally occurs. I tested other programs too but not faced such problem. Please help me. Thanks in advance.

I changed link to link1 in every place in my program.Now I am getting a new error which is given below.

pllab52.cpp: In member function ‘void link1<T>::addatbeg(T)’:
pllab52.cpp:40:37: error: there are no arguments to ‘malloc’ that depend on a template parameter, so a declaration of ‘malloc’ must be available [-fpermissive]
pllab52.cpp:40:37: note: (if you use ‘-fpermissive’, G++ will accept your code, but allowing the use of an undeclared name is deprecated)
pllab52.cpp: In member function ‘void link1<T>::addatmid(T, T)’:
pllab52.cpp:65:37: error: there are no arguments to ‘malloc’ that depend on a template parameter, so a declaration of ‘malloc’ must be available [-fpermissive]
pllab52.cpp: In member function ‘void link1<T>::addatbeg(T) [with T = int]’:
pllab52.cpp:82:18:   instantiated from here
pllab52.cpp:40:6: error: ‘malloc’ was not declared in this scope
pllab52.cpp: In member function ‘void link1<T>::addatmid(T, T) [with T = int]’:
pllab52.cpp:86:20:   instantiated from here
pllab52.cpp:65:6: error: ‘malloc’ was not declared in this scope

Answer 1

link(2) is a Linux system call that creates a hardlink to a file. Either rename your type or put it in a namespace.