Final answer:
The line 'InchSize totalSize;' is a declaration of a variable named totalSize of the class InchSize in C++, used to create an object that can store and manipulate inch measurement data.
Step-by-step explanation:
The line 'InchSize totalSize;' is used in the context of programming. Specifically, this line of code appears to be written in C++ and is used to declare a variable named totalSize of the class InchSize. This means that totalSize is an object that will hold data and functions related to inch measurements, assuming the InchSize class is defined to handle such information.
This declaration does not perform a mathematical operation nor is it used for error handling; it is simply the creation of a variable that can later be used in the program to store and manipulate data using the methods and attributes defined in the InchSize class.