c++ - Strange behavior of null pointer -

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this question has answer here:

i created null pointer of class app, somehow method of null object(of app) working. here code:

#include "app.h" #include <iostream> using namespace std; int main() {     app* pointer = null;     pointer->print();      system("pause"); }

attached header file

#pragma once #include <iostream> using namespace std; class app { private:     int x;     int y; public:     app(void);     ~app(void);     app(int a, int b)     {         x=a;         y=b;     }     void print()     {         cout<<"hello world"<<endl;     } };

the running result screen in : hello world. why that?

undefined behaviour - undefined. can happen, including appearance of behaving correctly.

for case, specifically, might want check out generated assembly program. you'll find compiler has optimized code , inlined printout or called directly rather invoking through pointer/table lookup.


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