Initializing Array of Pointers to nullpointer

Question

Hello stackover flow community, I'm trying initialize two empty array of pointers but getting this error on Visual Studio 2013:

Unhandled exception at 0x011C5E9C in 45CProject.exe: 0xC0000005: Access violation writing location 0x00000000.

Here is my code:

 #include <iostream>
using namespace std;
int main(){
 int* a[10] = { nullptr };
 int* b[10] = { nullptr };
 *a[0] = 2;
 *b[0] = 4;
 cout << "a[0] = " << *a[0] << endl;
 cout << "b[0] = " << *b[0] << endl;
 return 0;
}

Much Appreciated!

Answer 1

Yyou have an array of pointers. *a[0] means "data that first element(is a pointer) of the array points to. They don't point to anywhere since you initialized them with nullptr. This causes your access violation error;

• SaltAndPepper: How could I make the first element point to something after I made it point to nothing?
• SaltAndPepper: Does that mean I have to re-initialized to a non-null pointer
• sithereal: either initialze them with an actual address or give this address later. ex: int num; a[0] = # now you can use *a[0] to change the value in num.

Answer 2

You initialized a[0] to nullptr (0x00000000), then *a[0] = 2; attempts to write on this position, which results in an access violation.