Segmentation fault (core dumped) caused by delete

Question

I have encountered an error when delete some memory allocated for an object. Could you please help me analyze why it occurs? The error results from the statement of 'delete foo'.

// pointer to classes example
#include <iostream>
using namespace std;

class Rectangle {
  int width, height;
public:
  Rectangle(int x, int y) : width(x), height(y) {}
  int area(void) { return width * height; }
};


int main() {
  Rectangle obj (3, 4);
  Rectangle * foo, * bar, * baz;
  foo = &obj;
  bar = new Rectangle (5, 6);
  baz = new Rectangle[2] { {2,5}, {3,6} };
  cout << "obj's area: " << obj.area() << '\n';
  cout << "*foo's area: " << foo->area() << '\n';
  cout << "*bar's area: " << bar->area() << '\n';
  cout << "baz[0]'s area:" << baz[0].area() << '\n';
  cout << "baz[1]'s area:" << baz[1].area() << '\n';       
  delete bar;
  delete[] baz;
  delete foo; // This is the statement caused the error!!

  return 0;
}

/************************Output***************************************/

sh-4.2# main                                               
obj's area: 12                                             
*foo's area: 12                                            
*bar's area: 30                                            
baz[0]'s area:10                                           
baz[1]'s area:18                                           
Segmentation fault (core dumped)                           
sh-4.2#                                                    

Answer 1

You should only use delete for memory that was allocated using new.

obj has automatic storage duration - it will be destroyed when it goes out if scope. You don't need to manually delete it, iin fact doing so is an error, as you have seen.

Answer 2

Only delete the objects you created via new

Answer 3

Your problem in is because of the fact that you trying to delete something beyond the reach of your program, in the sense an address that is not in your scope.

That is so because you give some random address to delete . delete bar , where bar is allocated memory in stack is presumed to be in heap, which is not true and hence you get a crash.