A very useful addition to the C# language is the params parameter, which lets you define a method that can accept a variable number of arguments. The params parameter must be a single dimension or jagged array. When calling viewAddresses() , we pass in four string arguments. The number of arguments is variable and will be converted to a string automatically. In viewAddresses() we use a foreach loop to print each of these strings . Instead of the list of string arguments, the input could have also been a string array. The params parameter is considered an input only parameter and any changes affect the local copy only.