load std::map from text file

Question

This is a very simple thing, so I want to keep it as simple as it sounds. All I want is to load a bunch of key-value paires from a file, and populate them in to a map. I do

Answer 1

Since you seem to want the simplest thing humanly possible, I'm going to suggest something incredibly simple that may or may not work based on your map contents. If your map data values are strings that include spaces, this wont work. If they're strings without spaces, or numeric, you're set.

This isn't tested code, but it's close and simple so you should be fine even if it doesn't quite compile. Just change KeyType and ValueType to int, string, float, or whatever you're actually using in the file.

Set up file like:

key value
key2 value2
key3 value3
key4 value4

Read like:

KeyType key;
ValueType value;

std::map<KeyType, ValueType> myMap;
while (infile >> key >> value)
    myMap[key] = value;

Answer 2

If you are in the MS world you can use

GetPrivateProfileSectionNames
GetPrivateProfileString
WritePrivateProfileString

to read from ini file or regestry. If you want to write Unicode make sure a newly created file gets the BOM of UTF16.