Question - Give a detailed explanation of the differences between ref and out keywords.
Answer -
In any C# function, there can be three types of parameters, namely in, out and ref. Although both out and ref are treated differently at the run time, they receive the same treatment during the compile time. It is not possible to pass properties as an out or ref parameter. Following are the differences between ref and out keywords:
- Initializing the Argument or Parameter – While it is not compulsory to initialize an argument or parameter before passing to an out parameter, the same needs to be initialized before passing it to the ref parameter.
- Initializing the Value of the Parameter – Using ref doesn’t necessitate for assigning or initializing the value of a parameter before returning to the calling method. When using out, however, it is mandatory to use a called method for assigning or initializing a value of a parameter before returning to the calling method.
- Usefulness – When the called method requires modifying the passed parameter, passing a parameter value by Ref is useful. Declaring a parameter to an out method is appropriate when multiple values are required to be returned from a function or method.
- Initializing a Parameter Value in Calling Method – It is a compulsion to initialize a parameter value within the calling method while using out. However, the same is optional while using the ref parameter.
- Data Passing – Using out allows for passing data only in a unidirectional way. However, data can be passed in a bidirectional manner when using ref.