c++ - Explanation for a memory error result [compiler behavior] -

this question has answer here:

• c++ delete - deletes objects can still access data? 13 answers

first off, question compiler behavior not correct code either!

here's code cannot explain myself why i've got results. i know has memory error (deleting pointer in other scope , before done it) results only last element problematic. why last element has raw generated rand number?

#include <iostream>  using namespace std;  void populate(int *arraytopopulate, int arraysize);  int main() {     int *ptr;     ptr = new int[100];      populate(ptr, 100);      (int = 0; < 100; i++)         cout << ptr[i] << endl;      return 0; }  void populate(int *arr, int size) {     (int = 0; < size; i++) {          arr[i] = rand() % 100 + 1;     }      delete [] arr; } 

the results:

8 50 74 59 31 73 45 79 24 10 41 66 93 43 88 4 28 30 41 13 4 70 10 58 61 34 100 79 17 36 98 27 13 68 11 34 80 50 80 22 68 73 94 37 86 46 29 92 95 58 2 54 9 45 69 91 25 97 31 4 23 67 50 25 2 54 78 9 29 34 99 82 36 14 66 15 64 37 26 70 16 95 30 2 18 96 6 5 52 99 89 24 6 83 53 67 17 38 39 2687021

the result ended totally implementation dependant... ran in on msvc 2015 , got bunch of random negative , positive numbers outside range of generated sequence.