Question

该程序适用于使用模板的链接列表。

 #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();
 }

同样的程序在Windows 7开发C ++编译器上运行正常，而在linux g ++编译器上它会产生以下错误。

 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

两个C ++程序的行为都不同。是因为两者都有不同的编译器还是什么？还请告诉解决方案来解决这个问题。请解释通常何时出现这类问题。我也测试了其他程序，但没有遇到这样的问题。请帮我。提前谢谢。

我在程序的每个地方都更改了link1的链接。现在我收到一个新的错误，如下所示。

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)是一个Linux系统调用，用于创建文件的硬链接。重命名您的类型或将其放在命名空间中。

相同的程序在Windows和Linux上表现不同

1 个答案: