Chapter 9, Problem 7AW

Program Plan Intro

Dictionary:

• A dictionary is referred to as an object, which is used to store a collection of data.
• Dictionary consists of two parts, such as a key and a value.
• Dictionary is also known as key-value pairs.
• Each key consists of a specific value and can be used for locating that value.
• The general format to declare a Dictionary object is as follows:

  Dictionary<KeyType, ValueType> Dname = new Dictionary<KeyType, ValueType>();

• In the above format,
  • KeyType refers to the data type of each element’s key.
  • ValueType refers to the data type of each element’s value.
  • Dname refers to the Dictionary name.
• The general format to add an element to a Dictionary object using an Add method is as follows:

dictionaryName.Add(key, value);

• In the above format,
  • dictionaryName refers to the Dictionary name.
  • key refers to the key.
• If a key exists already in the Dictionary, an exception will be thrown.
• If a key does not exist in the Dictionary, then it is added to the Dictionary along with its associated value.