What is the purpose of parentheses () in a programming expression?

The purpose of parentheses in a programming expression is primarily to group expressions. This grouping allows the programmer to indicate the order in which operations should be evaluated, particularly in the case of complex mathematical calculations or logical conditions. For instance, in an expression like (2 + 3) * 4, the parentheses ensure that the addition operation is performed first, resulting in 5, before multiplying by 4 to get 20.

Additionally, parentheses are often used in functions to enclose parameters, highlighting their role in defining which values should be passed into the function. This grouping capability makes parentheses a crucial tool in controlling the precedence of operations and ensuring code executes precisely as intended.

While some other options mention processes related to programming, they do not accurately represent the specific function of parentheses. Terminating expressions is related to syntax but not specifically tied to parentheses, initiating loops is controlled by keywords like "for" or "while," and variable declaration involves specific syntax rather than the use of parentheses as a grouping tool.