In programming, what is an expression?

An expression in programming is defined as a combination of explicit values, variables, operators, and functions that are evaluated to produce another value. This means that an expression can involve various components such as numbers, mathematical operations (like addition or multiplication), and logical conditions, which when combined, evaluate to a single result.

For instance, in the expression 3 + 5, both 3 and 5 are explicit values, and the + is an operation. When evaluated, the expression produces the result 8. Similarly, more complex expressions can involve variables and multiple operations, such as x * (y + z), where x, y, and z could be variables containing values.

This definition sets expressions apart from constructs that do not evaluate to a value, such as flow-control statements (which alter the flow of execution in a program) or data structures (which store and organize data). Additionally, methods for debugging code do not produce values on their own but rather assist developers in finding and resolving issues in their code. Thus, the correct answer captures the essence of what an expression is in programming terms.