Thread: Meaning Of A Error Sentense

I got an Error when i am compiling a program
i know wut's wrong with it,and i have correct it back,
however,i dont understand the error msg that it show

"pure specifier can only be specified for functions"

wut does this sentense means?

Thx for helps!

Show some code. You've probably got an error around a pure virtual function somewhere but without seeing the code its very hard to tell.

Here's the code:
#include <iostream.h>

class ctry
{
public:
int x=12;
};

int main()
{
ctry test1;
cout << test1.x << "\n";
return 0;
}

i know where the problem is,i shouldnt assign the value for x,right?
but i just want to know wut
"pure specifier can only be specified for functions"
means

class ctry
{
public:
int x=12;
};

If you try to assign a value to something in a class the compiler will think you want it to be pure which is only allowed for functions. Even then you should also get an error that only =0 is allowed as a pure specifier. What you want to do is provide a constructor that assigns the value to x when the object is created.

Code:

#include <iostream>
using namespace std;

class ctry 
{ 
public:
  ctry(){ x = 12; };
  int x; 
};

int main() 
{ 
  ctry test1; 
  cout << test1.x << "\n"; 
  return 0; 
}

One other point, use code tags when posting code. Small snippets are easy to read but naything longer than a few lines is almost impossible.

Code:

#include <iostream>
using namespace std;

class ctry 
{ 
public:
  ctry(){ x = 12; };
  int x; 
};

int main() 
{ 
  ctry test1; 
  cout << test1.x << "\n"; 
  return 0; 
}

If you try to assign a value to something in a class the compiler will think you want it to be pure which is only allowed for functions. Even then you should also get an error that only =0 is allowed as a pure specifier. What you want to do is provide a constructor that assigns the value to x when the object is created.

Wut do u mean by "Pure"?

Even then you should also get an error that only =0 is allowed as a pure specifier.

Then why inside the constructor,u assign the x to be 12
but not =0?

A pure function in a class means that that class is abstract and no objects of it can be made, it can only be inherited. In the class declaration you can only assign a value when you want a function to be pure and that value has to be 0.

Code:

void function() =0;

Assigning 12 to a member of the class in the constructor and declaring a function to be pure virtual are two unrelated things. You can assign values to members in the methods, but not in the class declaration

Code:

class test
{
public:
  int x = 0 // NO!
  int y;
  void setY() { y = 0; }; // Yes
};