&。 Computer programs are closely related to mathematical symbols, which are called "and" symbols. & is a logical processing symbol, which is mainly used to judge whether it is true, such as true &；; False = false, true & true = true, false & false = false. From these examples, we can see that the sign of sum means that all the sub-conditions are true, then true, otherwise false.

And the symbol is [&&; ], and the symbol is true only when all conditions are true, for example, true &；; & false & true & true returns false, true &; & true & & kloc-0/. & The result returned is true.

C language provides a set of logical operators: OR (||) and (&; &), not (! ), respectively corresponding to OR, AND and NOT operations in propositional logic.

Logical operator: or ||. In propositional logic, when P= 1 or Q= 1, P||Q is equal to 1.

Logical operators: and &；; & amp。 In propositional logic, when P= 1 and Q= 1, P &；; & ampq is equal to 1.

Logical Operator: No! . In propositional logic, when p equals 0! P equals 1, and vice versa.