C# equivalent of C++ map<string,double>

Question

I want to keep some totals for different accounts. In C++ I'd use STL like this:

map<string,double> accounts;

// Add some amounts to some accounts.
accounts["Fred"] += 4.56;
accounts["George"] += 1.00;
accounts["Fred"] += 1.00;

cout << "Fred owes me $" << accounts['Fred'] << endl;

Now, how would I do the same thing in C# ?

Answer 1

Roughly:-

var accounts = new Dictionary<string, double>();  // Initialise to zero...  accounts["Fred"] = 0; accounts["George"] = 0; accounts["Fred"] = 0;  // Add cash. accounts["Fred"] += 4.56; accounts["George"] += 1.00; accounts["Fred"] += 1.00;  Console.WriteLine("Fred owes me ${0}", accounts["Fred"]); 

Answer 2

Dictionary<string, double> accounts; 

Answer 3

Although System.Collections.Generic.Dictionary matches the tag "hashmap" and will work well in your example, it is not an exact equivalent of C++'s std::map - std::map is an ordered collection.

If ordering is important you should use SortedDictionary.

Answer 4

You want the Dictionary class.