using namespace Exercise; does not cause ival"s redeclaration,
but using Exercise::ival; instead leads to why redeclaration is;
such as the following code:
-sharpinclude <iostream>
using namespace std;
namespace Exercise
{
int ivar = 0;
double dvar = 0;
const int limit = 1000;
}
// using namespace Exercise;
using Exercise::ivar;
int ivar = 0;
namespace is to solve the problem of naming conflicts, but your using Exercise::ivar; is equivalent to the ivar variable in Exercise , that is, it is not ivar and using Exercise::ivar that conflicts, but you declare using Exercise::ivar
the following code will be fine, because there is no declare using Exercise::ivar
-sharpinclude <iostream>
using namespace std;
namespace Exercise
{
int ivar = 0;
double dvar = 0;
const int limit = 1000;
}
// using namespace Exercise;
int ivar = 0;
int main()
{
cout<<Exercise::ivar;
cout<<ivar;
return 0;
}
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