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2.4 ARITHMETIC EXPRESSIONS

Summary of Arithmetic Expressions The sources discuss arithmetic expressions in programming, specifically focusing on their evaluation and the importance of operator precedence. An arithmetic expression combines items like variables, literals, operators, and parentheses to produce a value. [1] Valid expressions must follow specific rules, such as the requirement of an operator between variables. For example, "x + 1" is valid, while "x (x - y)" is not. [2] Evaluating expressions involves determining their final value. For instance, if x is 5, the expression "x + 1" evaluates to 6. [3] Operator precedence dictates the order in which operations are performed in an expression. The order follows standard mathematical conventions: Parentheses take precedence, followed by unary negation (-). Multiplication and division (*, /) have equal precedence and are evaluated next. Finally, addition and subtraction (+, -) are evaluated last. [4] When multiple operators of equal precedence appear, evaluation proceeds from left to right. [4] Using parentheses strategically is crucial for clarity and avoiding errors. For example, "5 + 5 * 2" evaluates to 15, while "(5 + 5) * 2" evaluates to 20. [5, 6] Expressions are used in programming for various purposes, including calculating values based on user input or other variables. [6, 7] The sources emphasize that understanding operator precedence and using parentheses effectively are essential for writing accurate and predictable code.