C++ Primer Plus

Side Effects and Sequence Points

Let’s take a closer look at what C++ does and doesn’t say about when increment operators take effect. First, recall that a side effect is an effect that occurs when evaluating an expression modifies something, such as a value stored in a variable. A sequence point is a point in program execution at which all side effects are guaranteed to be evaluated before going on to the next step. In C++ the semicolon in a statement marks a sequence point. That means all changes made by assignment operators, increment operators, and decrement operators in a statement must take place before a program proceeds to the next statement. Some operators that we’ll discuss in later chapters have sequence points. Also the end of any ...