What is the precedence of logical operators in C language?

The precedence of logical operators in C language from high to low is:! (logical NOT), && (logical AND), || (logical OR). The value of a logical expression is a logical value; logical values ​​are divided into logical true values ​​and logical false values. During judgment, only zero values ​​are judged as logical false values ​​(false), and all non-zero values ​​can be judged as logical true values. value(true).

#C language provides the following three logical operators.

One yuan:! (logical not). Binary: && (logical AND), || (logical OR).

Among the above three logical operators, logical NOT ! has the highest priority, logical AND && comes second, and logical OR || has the lowest priority.

The value of a logical expression is a logical value, that is, Boolean type (bool). This type is new in C99. Some compilers may not support this type yet.

Logical values ​​are divided into logical true values ​​and logical false values. Under normal circumstances, during judgment, only zero values ​​are judged as logical false values ​​(false), and all non-zero values ​​can be judged as logical true values ​​(true); when storing and representing, usually, 1 is used to represent logical values. True value, 0 represents a logical false value.

The operation rules of logical AND && operator: The result is true only when both operands are logically true. In all other cases, the result is false.

The operation rules of logical OR || operator: The result is false only when both operands are logically false. In all other cases, the result is true.

int a=3,b=5;

Then there are:

!a: Since a is non-zero, it is true, !a is false, and its value is 0.

a||b: Since both a and b are non-zero and both are true, the result of logical OR is true and its value is 1.

a&&b: Since both a and b are non-zero and both are true, the result of logical AND is true and its value is 1.

!a||b&&2: Since logical negation! has the highest priority, it is combined with a first, and && has a higher priority than ||, which is equivalent to (!a)||(b&&2), that is, 0|| 1 is true, its value is 1.

Logical AND &&, logical OR || all have "short circuit" characteristics:

Logical AND && "short circuit": When the left operand of logical AND && is logical When false, it is enough to judge that the result of the logical operation is false, so the right operand will no longer be executed.

Logical OR || "Short circuit": When the left operand of logical OR || is logically true, it is enough to judge that the result of the logical operation is true, so the right operand will no longer be executed.

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