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!

sithereal · Accepted Answer · 2015-02-26 02:29:52Z

2

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;

answered Feb 26, 2015 at 2:29

sithereal

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3 Comments

SaltAndPepper Over a year ago

How could I make the first element point to something after I made it point to nothing?

SaltAndPepper Over a year ago

Does that mean I have to re-initialized to a non-null pointer

sithereal Over a year ago

either initialze them with an actual address or give this address later. ex: int num; a[0] = &num; now you can use *a[0] to change the value in num.

kalkanistovinko · Accepted Answer · 2015-02-26 03:14:03Z

0

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

answered Feb 26, 2015 at 3:14

kalkanistovinko

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