Often you want to ask more than one relational question at a time. “Is it true that x is greater than y, and also true that y is greater than z?” A program might need to determine that both of these conditions are true, or that some other condition is true, in order to take an action.
Imagine a sophisticated alarm system that has this logic: “If the door alarm sounds AND it is after six p.m. AND it is NOT a holiday, OR if it is a weekend, then call the police.” The three logical operators of C++ are used to make this kind of evaluation. These operators are listed in Table 4.2.
|AND||&&||expression1 && expression2|
|OR||||||expression1 || expression2|