Public to add a third behavior is {}, I know this is the destructor, without what effect, if the test, but can't read, please guide, thank you very much

CodePudding user response:

Plus is a function definition (that is, the body of the function), not just function declarations,
For example,
Void fun ();//this is function declaration
Void fun () {printf (" a "); }//this is a function definition, {} is executing code inside, can be null, that is what all don't perform,