In c++! How to use

The exclamation point (!) in C represents a logical NOT operation, which inverts the Boolean value: if the value is true, return false; if the value is false, return true.

Exclamation mark (!) usage in C

In C, the exclamation mark (!) operator represents logic Not operation. Its function is to invert a Boolean value (true or false).

Syntax:

!expression

Among them, expression is the Boolean expression to be inverted.

Return value:

This operator returns a Boolean value, indicating the result of the inversion of the expression. Specifically:

• If expression is true, returns false.
• Returns true if expression is false.

Example:

bool isTrue = true;
bool isFalse = false;

bool notTrue = !isTrue; // false
bool notFalse = !isFalse; // true

Other usages:

In addition to the logical NOT operation, the exclamation point is also used in C It has the following usage:

• Destructor prefix: Adding an exclamation mark before the destructor declaration indicates that the function is a virtual destructor.
• Throw an exception: The exclamation mark can be used in the throw statement to throw an exception object.
• Macro operations: You can use macro operators with exclamation points to perform macro expansion.

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