Arizona State University (ASU) CSE240 Introduction to Programming Languages Midterm Practice Exam

A data type is fundamentally important in programming as it specifies the type of data that a variable can hold. This means it determines the kind of operations that can be performed on the data and how the data is stored, which influences the memory layout. By defining the scope of acceptable values a variable can represent—such as integers, floating-point numbers, characters, or more complex structures—data types help ensure that the correct type of data is used in calculations, comparisons, and other operations.

Choosing the right data type is crucial for both performance and correctness in programs. For example, if a variable is defined as an integer data type, it cannot hold decimal values, which would lead to errors if a floating-point number is assigned to it. Thus, understanding that a data type defines what kind of data a variable can hold is essential for writing effective and error-free code. Other options addressed aspects related to data types but did not comprehensively capture their primary role in programming.