In programming, an expression is defined as a combination of items, such as variables, literals, operators, and function calls, that evaluates to produce a value. This means that when an expression is executed, it computes a result based on the rules of the programming language being used. For instance, in the expression 5 + 3, the items involved (the numbers and the operator) combine to evaluate to the value 8.
This foundational understanding of expressions is crucial, as they are used throughout programming to manipulate data, perform calculations, and control program logic. The clarity that expressions provide in calculating values distinguishes them from other concepts in programming, such as constants or variables, which do not inherently compute values on their own. By understanding that an expression is primarily about performing evaluations to acquire values, you can better grasp how they are utilized in various programming contexts.