问题
When I run the following code:
#include <iostream>
using namespace std;
main(){
//declare:
char* TestArray = new char[16];
for(char i=0; i<16; i++){
TestArray[i]=rand() % 10;
}
//output Array:
for(char i=0; i<16; i++){
cout << int(TestArray[i]) << " ";
}
//delete it:
delete[] TestArray;
//output result:
for(char i=0; i<16; i++){
cout << int(TestArray[i]) << " ";
}
the outcome is:
3 6 7 5 3 5 6 2 9 1 2 7 0 9 3 6 //declared Array
0 0 0 0 0 0 0 0 9 1 2 7 0 9 3 6 //'deleted' Array
So, the Problem is, that delete[] is not deleting the entire Array. If I make an Array of int, the number of deleted slots is 2. I am using g++/gcc 4.9 under Arch Linux.
What is the reason to that and how will I be able to fix it?
By the way: the number of '0's in the 'deleted' Array seems to be equivalent to:
sizeof(TestArray)/sizeof(TestArray[0])
回答1:
You are accessing memory after it has been deleted. That invokes undefined behaviour. There may be a runtime error, or maybe not.
All that it means to delete a block of memory is that you are promising not to use that pointer again. The system is thus free to do what it wants with that memory. It may re-use it. It may do nothing with it initially. You promised not to use the pointer again, but then broke that promise. At that point anything can happen.
来源：https://stackoverflow.com/questions/23461434/c-array-why-is-delete-not-working