do...while loop

[metalinc]

i'm trying to do a do while loop, to keep printing the data that matches the key of mymap.
my while statement printed an endless loop....
What should the while statement be??

do
{
  if(mymap.find(input)!= mymap.end())
  {
      cout<< mymap.find(input)->second<<endl;
      mymap.find(input)++;
  }
  else
     cout<<"No word(s) found."<<endl;
}
  while(mymap.find(input)!= mymap.end()); //this cause endless loop

[AdrianH]

i'm trying to do a do while loop, to keep printing the data that matches the key of mymap.
my while statement printed an endless loop....
What should the while statement be??

do
{
  if(mymap.find(input)!= mymap.end())
  {
      cout<< mymap.find(input)->second<<endl;
      mymap.find(input)++;
  }
  else
     cout<<"No word(s) found."<<endl;
}
  while(mymap.find(input)!= mymap.end()); //this cause endless loop

A map is a way of mapping a key to an item. That is a 1:1 mapping. Find, finds that item using the key.

See here for more details.

Perhaps you want a map of a key to a list or other container?


Adrian

[weaknessforcats]

Are you using a multimap? The answer must be yes or you can't have duplicate keys.

Assuming that, your code should look like:

[code=cpp]
pair< multimap< etc>::iterator, multimap< etc>::iterator > range;

range = equal_range(mym ap.begin(), mymap.end(), input);

multimap< etc>::iterator itr = range.first;

while (itr != range.second)
{
//cout your data
itr++;
}
[/code]

I didn't compile this. This is just to give you the idea. equal_range is an STL algorithm that return a pair of iterators that bracket the range of elments in the constainer that have the specified value.

The first iterator you an use as a begin() and the second iterator you can use an end().

[AdrianH]

Are you using a multimap? The answer must be yes or you can't have duplicate keys.

Assuming that, your code should look like:

[code=cpp]
pair< multimap< etc>::iterator, multimap< etc>::iterator > range;

range = equal_range(mym ap.begin(), mymap.end(), input);

multimap< etc>::iterator itr = range.first;

while (itr != range.second)
{
//cout your data
itr++;
}
[/code]

I didn't compile this. This is just to give you the idea. equal_range is an STL algorithm that return a pair of iterators that bracket the range of elments in the constainer that have the specified value.

The first iterator you an use as a begin() and the second iterator you can use an end().

Cool, good to know. ;)


Adrian