CODEWITHSUNDEEP
c++arrays
Crazy
Crazy

Reputation: 458

Issue with Array assignment

I am having an issue with outputting an array. When I output each element without a for loop, the program runs fine. When I try to output with a for loop, the program crashes the first time I set an element in the array. I have marked the line where the program crashes when I uncomment out the for loop. My sort seems to work fine and the program is crashing way before that, so I'm pretty sure that isn't the issue. Any ideas why the 2nd for loop would crash the program at the specified line?

int main()
{
   int* Array;
   int j = 5;
   for(int i=0; i<5; i++)
   {
       Array[i] = j; //Crashes here with 2nd for loop uncommented
       cout << Array[i] << endl;
       j--;
   }
    Array = insertion_sort(Array);

    cout << Array[0] << endl;
    cout << Array[1] << endl;
    cout << Array[2] << endl;
    cout << Array[3] << endl;
    cout << Array[4] << endl;



   /*for(int k=0; k <5; k++)
   {
      cout << Array[k] << endl;
   }*/


}

Upvotes: 1

Views: 105

Answers (2)

Eric B
Eric B

Reputation: 4437

You are accessing the pointer before initializing it. You should change

int* Array;

to

int* Array = new int[5]; // There are 5 ints in my array

and make sure to 

delete[] Array;

at the end, or even better:

int Array[5]; // This way you don't need the new keyword, so you won't need to delete[] later

Upvotes: 3

Dakotah Hicock
Dakotah Hicock

Reputation: 390

Right now, your array is not instanciated. It's just a pointer. You need to choose how large of an array you want before you can start writing to it.

int* Array = new int[5];
int j = 5;
for(int i=0; i<5; i++)
{
    Array[i] = j; //Crashes here with 2nd for loop uncommented
    cout << Array[i] << endl;
    j--;
}

Upvotes: 1

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