What is a constructor in programming?

A constructor is a specific type of function used in programming, particularly in object-oriented programming languages. Its primary role is to initialize new objects of a class when they are created. When an object is instantiated, the constructor is automatically called to set up the object's initial state, usually by assigning values to its attributes or properties.

This is crucial for ensuring that an object starts its life in a well-defined state, which can include setting default values, establishing connections to resources, or performing any necessary setup tasks. Each class may have its own constructor, and there can be multiple constructors with different parameters (known as constructor overloading) to provide flexibility in how objects of that class can be created.

Other options do not accurately reflect the purpose and functionality of constructors. For instance, while creating user interfaces, handling exceptions, or debugging code are important aspects of programming, they do not define what a constructor is or its role in object initialization.