Multiple file handeling

I have three files
1. space1.hpp 2. space2.hpp and 3. main.cpp
space1.hpp contains:

Code:

using namespace std;
namespace space1        {
        class sp1{

                public:
                sp1(){
                }

        };
}

space2.hpp contain

Code:

#include "space1.hpp"
// want to use sp1 class here
using namespace std;
using namespace1;
namespace space2        {
        class sp2{

                public:
                sp2(sp1 sp){
                }

        };
}

& main.cpp contains:

Code:

#include "space1.hpp"
#include "space2.hpp"
// want to use both the class sp1 and sp2 here
using namespace std;
using namespace space1;
using namespace space2;

int main(){
        sp1 s1 =sp1();
        sp2 s2 =sp2(s1);
}

Error is coming:

Code:

In file included from space2.hpp:1,
                 from main.cpp:2:
space1.hpp:4: error: redefinition of ‘class space1::sp1’
space1.hpp:4: error: previous definition of ‘class space1::sp1’
In file included from main.cpp:2:
space2.hpp:5: error: expected nested-name-specifier before ‘namespace1’
space2.hpp:5: error: ‘namespace1’ has not been declared
space2.hpp:11: error: expected ‘)’ before ‘sp’
main.cpp: In function ‘int main()’:
main.cpp:10: error: no matching function for call to ‘space2::sp2::sp2(space1::sp1&)’
space2.hpp:8: note: candidates are: space2::sp2::sp2()
space2.hpp:8: note:                 space2::sp2::sp2(const space2::sp2&)

kindly fix it!

kindly fix it!

Hmmm, there are better ways to ask for assistance rather than making demands.

#1. Learn about header inclusion guards and make use of them in your header files. This will help avoid those pesky "redefinition" errors you are getting.

#2. Avoid blanket "using namespace" declarations in your header files. They open up that entire namespace to any source file that just happens to include said headers. Within the headers, try to always explicitly qualify the namespace of any objects which require it. If you want to put in a using namespace declaration, then do it at the source level and not the header level.

Doing the above, your two header files should look like the following:

Code:

#ifndef SPACE1_H
#define SPACE1_H

namespace space1 {
    class sp1 {
    public:
        sp1() {
        }
    };
}

#endif

Code:

#ifndef SPACE2_H
#define SPACE2_H

#ifndef SPACE1_H
#include "space1.hpp"
#endif

namespace space2 {
    class sp2{
    public:
        sp2(space1::sp1 sp){
        }
    };
}

#endif