list of map iterator

[Filippov]

map<int,int> coincidence;
list<map<int,int>> coincidences;
list<map<int,int>>::iterator list_it;
map<int,int>::iterator map_it;

coincidence[0] = 1;
coincidence[1] = 5;
coincidence[2] = 10;
coincidences.push_back(coincidence);

list_it = coincidences.begin();
map_it = (*list_it).begin();

Last line failed due to:
Error: Incorrect referencing of list_it rain.cc:365:
Error: illegal pointer to class object list_it 0x0 2610 rain.cc:365:
*** Interpreter error recovered ***

Where am i wrong?

[Mythios]

I'm a little confused I might be missing what your actual problem is? But mine builds and runs with no errors?

[lloydchristmas759]

g++ 4.3.2 says:

test.cpp:9: error: ‘>>’ should be ‘> >’ within a nested template argument list
test.cpp:10: error: ‘>>’ should be ‘> >’ within a nested template argument list

but if I add spaces as it says, it compiles without error or warning.

What compiler are you using ?

[Mythios]

VS 2008 Professional and Express:

#include <iostream>
#include <map>
#include <list>
using namespace std;

int main()
{
	map<int,int> coincidence;
	list<map<int,int>> coincidences;

	list<map<int,int>>::iterator list_it;
	map<int,int>::iterator map_it;

	coincidence[0] = 1;
	coincidence[1] = 5;
	coincidence[2] = 10;
	coincidences.push_back(coincidence);

	list_it = coincidences.begin();
	map_it = (*list_it).begin();

	for(; map_it != (*list_it).end(); map_it++)
	{
		cout << "First  = " << map_it->first << endl;
		cout << "Second = " << map_it->second << endl;
	}

	return 0;
}

Works fine no issues.

[z05DSL3A]

In the current standard >> is always parsed as the right shift operator (IIRC, this will be changed in the next standard).

Some tool chains have already implemented this change.

[moorecm]

For portability, or more specifically compiler-independence, it is best to use "> >" with a space separating the two closing angle-brackets. This is certainly something to be familiar with, as not all error messages are so explicit.

You could use typedefs in this situation, as well. Here is an example:

typedef map<int,int>  CoinMap;
typedef list<CoinMap> ListOfCoins;
// etc...

CoinMap     coincidence;
ListOfCoins coincidences;
// etc...