Standard Template Library Programmer's Guide

[1] This member function relies on member template functions, which at present (early 1998) are not supported by all compilers. If your compiler supports member templates, you can call this function with any type of input iterator. If your compiler does not yet support member templates, though, then the arguments must either be of type const value_type* or of type multiset::const_iterator .

Associative Container, Sorted Associative Container, Simple Associative Container, Multiple Sorted Associative Container, set , map , multimap , hash_set , hash_map , hash_multiset , hash_multimap

Category: containers

Component type: type

Multimap is a Sorted Associative Container that associates objects of type Key with objects of type Data . multimap is a Pair Associative Container, meaning that its value type is pair . It is also a Multiple Associative Container, meaning that there is no limit on the number of elements with the same key.

Multimap has the important property that inserting a new element into a multimap does not invalidate iterators that point to existing elements. Erasing an element from a multimap also does not invalidate any iterators, except, of course, for iterators that actually point to the element that is being erased.

struct ltstr {

bool operator()(const char* s1, const char* s2) const {

return strcmp(s1, s2) < 0;

}

};

int main() {

multimap m;

m.insert(pair("a", 1));

m.insert(pair("c", 2));

m.insert(pair("b", 3));

m.insert(pair("b", 4));

m.insert(pair("a", 5));

m.insert(pair("b", 6));

cout << "Number of elements with key a: " << m.count("a") << endl;

cout << "Number of elements with key b: " << m.count("b") << endl;

cout << "Number of elements with key c: " << m.count("c") << endl;

cout << "Elements in m: " << endl;

for (multimap::iterator it = m.begin(); it != m.end(); ++it)

cout << " [" << (*it).first << ", " << (*it).second << "]" << endl;

}

Defined in the standard header map, and in the nonstandard backward-compatibility header multimap.h.

Multiple Sorted Associative Container, Pair Associative Container

• Data is Assignable.

• Compare is a Strict Weak Ordering whose argument type is Key .

• Alloc is an Allocator.

None.

All of multimap 's members are defined in the Multiple Sorted Associative Container and Pair Associative Container requirements. Multimap does not introduce any new members.