Re: Can associative arrays be implemented by operator overloading?
On Nov 21, 7:25 am, Old Wolf <oldw...@inspire.net.nz> wrote:
On Nov 21, 10:53 am, Ramon F Herrera <ra...@conexus.net> wrote:
On Nov 19, 11:40 pm, Ian Collins <ian-n...@hotmail.com> wrote:
std::map<std::string,int> myMap;
myMap["ramon"] = 42.
I am really a newbie when it comes to the "::" notation. Can somebody
please convert the above into an actual snippet? (i.e, code that
compiles)?
C++ supports a concept called "namespace". Basically, you can do
something like this:
#include<assert>
namespace mynamespace{
int variable;
}
namespace hisnamespace{
int variable;
}
int main(){
mynamespace::variable = 42;
hisnamespace::variable = 54;
assert(mynamespace::variable != hisnamespace::variable);
assert(&mynamespace::variable != &hisnamespace::variable);
return 0;
}
Note, however, that :: notation is used for more than just namespaces
(it's just that in the code shown it's for namespaces, and in my
experience you will more commonly use it for namespaces).
It is also used with class names and members.
class foo{
public:
int member();
}
int foo::member(){
std::cout << "this is foo's member()!" << std::endl;
}
#include <string>
#include <map>
#include <algorithm>
#include <iostream>
Note how the include filenames look like. The standard C++ headers do
not end in ".h". Secondly, you can include some C standard headers
using two different variants: something like #include<stdio.h> or
#include<cstdio>. There are differences between the two; IIRC the
most important difference is that functions included via <c...> are in
the std namespace.
void show_item( std::pair<std::string, int> item )
{
std::cout << "Key '" << item.first << "', value '" << item.second <<
"'\n";
std::cout is equivalent to stdout.
}
int main()
{
std::map<std::string, int> myMap;
myMap["ramon"] = 42;
myMap["joe"] = 22;
for_each( myMap.begin(), myMap.end(), show_item );
return 0;
}