Thread: Including header in order

Originally Posted by Tamim Ad Dari

So there is no way of making clear() as friend;

Yes there is, as you have already been advised. The fact you have chosen to disregard the advice in this thread does not mean that a solution does not exist.

Originally Posted by Tamim Ad Dari

how to copy paste errors in code blocks?? When I right click on the error button theres no options such as copy..

Make sure the logs are visible; select the "Build Log"
[F2 toggles the logs area]
Right click on the build log; use "select all".
Right click again and use "copy"

Code:

-------------- Clean: Debug in cpptest (compiler: GNU GCC Compiler)---------------

Cleaned "cpptest - Debug"

-------------- Build: Debug in cpptest (compiler: GNU GCC Compiler)---------------

mingw32-g++.exe -std=c++11 -Wall -fexceptions  -g  -Wmissing-include-dirs    -c V:\SourceCode\Projects\cpptest\main.cpp -o obj\Debug\main.o
V:\SourceCode\Projects\cpptest\main.cpp: In function 'int main()':
V:\SourceCode\Projects\cpptest\main.cpp:12:13: warning: unused variable 'ht' [-Wunused-variable]
V:\SourceCode\Projects\cpptest\main.cpp:12:19: warning: unused variable 'wd' [-Wunused-variable]
V:\SourceCode\Projects\cpptest\main.cpp:15:6: warning: variable 'c' set but not used [-Wunused-but-set-variable]
mingw32-g++.exe -std=c++11 -Wall -fexceptions  -g  -Wmissing-include-dirs    -c V:\SourceCode\Projects\cpptest\Screen.cpp -o obj\Debug\Screen.o
mingw32-g++.exe  -o bin\Debug\cpptest.exe obj\Debug\main.o obj\Debug\Screen.o    
Output size is 1.01 MB
Process terminated with status 0 (0 minutes, 2 seconds)
0 errors, 3 warnings (0 minutes, 2 seconds)

Tim S.

main.cpp

Code:

#include <iostream>
#include <string>
#include <vector>

#include "Window_mgr.h"

using namespace std;

int main()
{

Screen::pos ht=24,wd=10;
Screen scr(24,10,' ');
Screen *p=&scr;
char c=scr.get();
c=p->get();

}

Window_mgr.h

Code:

#ifndef WINDOW_MGR_H_INCLUDED
#define WINDOW_MGR_H_INCLUDED

#include <iostream>
#include <vector>

#include "Screen.h"

struct Window_mgr{

public:
    using ScreenIndex=std::vector<Screen>::size_type;
    void clear(ScreenIndex);
    ScreenIndex addScreen(const Screen&);
private:
    std::vector<Screen> screens{Screen(24,80,' ')};


};

void Window_mgr::clear(ScreenIndex i)
{
Screen &s=screens[i];
s.contents=std::string(s.width*s.height,' ');
}
Window_mgr::ScreenIndex Window_mgr::addScreen(const Screen &s)
{
    screens.push_back(s);
    return screens.size()-1;


}
#endif // WINDOW_MGR_H_INCLUDED

Screen.h

Code:

#ifndef SCREEN_H_INCLUDED
#define SCREEN_H_INCLUDED

#include <iostream>

class Screen{
    friend std::ostream& storeOn(std::ostream&,Screen&);
friend class Window_mgr;
friend void showscreen(const Screen&);
friend std::istream &read(std::istream&,Screen&);
public:
   typedef std::string::size_type pos;
   Screen()=default;
   Screen(pos ht,pos wd,char c):height(ht),width(wd),contents(ht*wd,c){}
   char get() const {return contents[cursor];}
   inline char get(pos ht,pos wd) const;
   Screen &move(pos r,pos c);
   void some_member() const;
   Screen &set(char);
   Screen &set(pos,pos,char);
   pos size() const;

private:
    mutable size_t access_ctr;
    pos cursor=0;
    pos height=0,width=0;
    std::string contents;
};

#endif // SCREEN_H_INCLUDED

Screen.cpp

Code:

#include "Screen.h"

using std::cout;
using std::endl;
using std::string;

Screen::pos Screen::size() const
{
    return height*width;
}
inline
Screen &Screen::move(pos r,pos c)
{
    pos row=r*width;
    cursor =row+c;
    return *this;
}
char Screen::get(pos r,pos c) const
{
    pos row=width*r;
    return contents[row+c];
}
void Screen::some_member() const
{
    ++access_ctr;
}
void showscreen(const Screen &in)
{
    for(unsigned i=0;i<in.height*in.width;++i)
{
    if(i&&i%in.width==0) cout<<endl;
    cout<<in.contents[i];
}
cout<<endl;
}
std::istream &read(std::istream &is,Screen &in)
{
    cout<<"Enter the height,width and character of the screen seperated by space "<<endl;
    is>>in.height>>in.width;
    char c=getwchar();
    string s(in.height*in.width,c);
    in.contents=s;
    return is;
}
inline Screen &Screen::set(char c)
{
    contents[cursor]=c;
    return *this;
}
inline Screen &Screen::set(pos r,pos col,char c)
{
    contents[r*width+col]=c;
    return *this;
}

The above code compiled for me; I just did all the suggestions in this thread and know how to understand most of the g++ error messages.
If you really wrote this code you know more C++ than I do; but, I know what compiler I am using and understand the tools I am using much better than you do. And, I can follow advise.

I did not even know the below line was possible in C++.

Code:

using ScreenIndex=std::vector<Screen>::size_type;

Tim S.

Originally Posted by stahta01

I did not even know the below line was possible in C++.

Code:

using ScreenIndex=std::vector<Screen>::size_type;

It's a new feature ratified in C++-11 (the 2011 C++ standard), and was not possible in previous standards.