Chapter 7

Arithmetic Expressions and Operators

• Unary operators have one operand, binary operators have two, and ternary operators have three operands
• Operator precedence rules define the order in which operators of different precedence levels are evaluated, typical levels include parentheses, unary operators, exponentiation, multiplication/division, and addition/subtraction
• Operator associativity rules define the order in which adjacent operators with the same precedence level are evaluated, with exceptions such as right-to-left associativity for certain operators
• In Ruby, arithmetic, relational, assignment operators, and others are implemented as methods, allowing them to be overridden by application programs
• Conditional expressions in C-based languages like C and C++ can be represented using the ternary operator, for example, average = (count == 0) ? 0 : sum / count
• Operand evaluation order starts with variables fetching values from memory, followed by constants, parenthesized expressions, and function calls
• Functional side effects occur when a function changes a two-way parameter or a non-local variable, which can lead to unexpected behavior in expressions
• Solutions to the problem of functional side effects include disallowing them in the language definition or fixing operand evaluation order
• Referential transparency in a program allows the substitution of expressions with the same value without affecting the program's behavior, making the program's semantics easier to understand
• Operator overloading, where an operator is used for more than one purpose, can aid readability but may also lead to potential problems and loss of readability
• Type conversions include narrowing and widening conversions, as well as mixed-mode expressions and coercions, which can decrease the type error detection ability of the compiler
• Explicit type conversions, also known as casting in C-based languages, allow for the explicit conversion of types, for example, (int)angle in C or float(sum) in F#