Question

Is there any difference between these two declarations?

int x[10];

vs.

int* x = new int[10];

I suppose the former declaration (like the latter one) is a pointer declaration and both variables could be treated the same. Does it mean they are intrinsically the same?

Answer 1

#include<iostream>    

int y[10];


void doSomething()
{
    int x[10];
    int *z  = new int[10];
    //Do something interesting

    delete []z;
}

int main()
{
    doSomething();

}

‏‏‏‏‏‏‏

int x[10]; 

– Creates an array of size 10 integers on stack.
– You do not have to explicitly delete this memory because it goes away as stack unwinds.
– Its scope is limited to the function doSomething()

int y[10];

– Creates an array of size 10 integers on BSS/Data segment.
– You do not have to explicitly delete this memory.
– Since it is declared global it is accessible globally.

int *z = new int[10];

– Allocates a dynamic array of size 10 integers on heap and returns the address of this memory to z.
– You have to explicitly delete this dynamic memory after using it. using:

delete[] z;