Re: assignment/initialization of container - map

From:

"Thomas Tutone" <Thomas8675309@yahoo.com>

Newsgroups:

comp.lang.c++

Date:

18 Jul 2006 13:28:45 -0700

Message-ID:

<1153254525.072613.215280@m79g2000cwm.googlegroups.com>

Victor Bazarov wrote:

Ron Natalie wrote:

xuatla wrote:

I want to define a map:

std::map<string, int> myMap;

e.g., the score of students. Then I can assign the value as follows:
myMap["stud1"] = 90;
myMap["stud2"] = 60;
...

My question now is: can I assign the name of many students in one
line? e.g., for array we have the following way:
int myArray[] = { 1, 3, 4, 5 };

Do we have similar way for map?
std::map<string, int> myMap = { ("stud1", 90), ("stud2", 60) };
// wrong co

No, map's not an aggregate.

The best you can do is something like:

struct apair {
const char* s;
int i;
} maptab[] = { { "stud1", 90 }, ....

for(apair* ap = maptab; ap != sizeof maptab/sizeof (apair); ++ap)
myMap[ap->s] = ap->i;

Shouldn't this work

std::map<string,int> myMap(maptab, maptab +
sizeof(maptab)/sizeof(*maptab));

I could be wrong about this, but I don't think that would work. The
map<string, int> constructor would be expecting iterators pointing to
pair<string, int>, and would get instead an iterator to struct { const
char*, int }. Unless there's some sort of implicit conversion going on
that I don't understand, your example shouldn't compile. Even if it
were a map<const char*, int>, I think it still wouldn't work, because a
struct { const char*, int } is different from a pair<const char*, int>.

Or maybe I'm wrong.

Best regards,

Tom