hashtable

I have hashtbles in array list. List<Hashtable<String, String>> info = new ArrayList<Hashtable<String, String>>(); Hashtable<String, String> hm = new Hashtable<String, String>(); // Put elements to the map hm.put("Read_Flag", s1); hm.put("sms_received_id", s2); hm.put("Sender_Id", s3); hm.put("Sender_Name", s4); hm.put("Patient_Name", s5); hm.put("Received_Date", s6); hm.put("Received_Text", s7); hm.put("Received_Text_Full", s8); hm.put("AttachmentFlag", s9); // Get a set of the entries Set<?> set = hm.entrySet(); // Get an iterator Iterator<?> it = set.iterator(); // Display elements while(it

This is not a question about the differences between Hashtable and HashMap . I understand that a Hashtable object cannot accept null values for either key or value entries, that it is synchronized collection, and that it uses slightly less memory than a HashMap . I'm wondering about the scenarios where it would be more appropriate to use a Hashtable instead of a HashMap . This is not a question about the differences between Hashtable and HashMap Well it is really... I'm wondering about the scenarios where it would be more appropriate to use a Hashtable instead of a HashMap . Precisely when you

I have a structure in C#: public struct UserInfo { public string str1 { get; set; } public string str2 { get; set; } } The only rule is that UserInfo(str1="AA", str2="BB").Equals(UserInfo(str1="BB", str2="AA")) How to override the GetHashCode function for this structure? aku MSDN : A hash function must have the following properties: If two objects compare as equal, the GetHashCode method for each object must return the same value. However, if two objects do not compare as equal, the GetHashCode methods for the two object do not have to return different values. The GetHashCode method for an

I need some sort of way to store key/value pairs where the value can be of different types. So I like to do: int i = 12; string s = "test"; double x = 24.1; Storage.Add("age", i); Storage.Add("name", s); Storage.Add("bmi", x); And later retrieve the values with: int a = Storage.Get("age"); string b = Storage.Get("name"); double c = Storage.Get("bmi"); How should a Storage like this look like? Thanks, Erik Well, you could use Dictionary<string, dynamic> in C# 4 / .NET 4 - but other than that, you can't do it with exactly the code shown because there's no type which is implicitly convertible to

I understand there is a hashing technique is applied to a key to store its value in the memory address. But I don't understand how the collision is happening here? Which hashing algorithm does Java use to create a memory space ? Is it MD5? The basic idea of HashMap is this: A HashMap is really an array of special objects that hold both Key and Value. The array has some amount of buckets (slots), say 16. The hashing algorithm is provided by the hashCode() method that every object has. Therefore, when you are writing a new Class , you should take care of proper hashCode() and equals() methods

I'm relatively new to C++. In Java, it's easy for me to instantiate and use a hashmap. I'd like to know how to do it in a simple way in C++, since I saw many different implementations and none of them looked simple to me. Most compilers should define std::hash_map for you; in the coming C++0x standard, it will be part of the standard library as std::unordered_map . The STL Page on it is fairly standard. If you use Visual Studio, Microsoft has a page on it. If you want to use your class as the value, not as the key, then you don't need to do anything special. All primitive types (things like