Question

int main(){
    int a[10][10];
    int **ptr =(int **)a;
    cout<<a<<endl<<ptr<<endl;
    cout<<*a<<endl<<*ptr<<endl;
    return 0;
}

Output of this code on my computer is

0021FC20
0021FC20
0021FC20
CCCCCCCC

Why is “a” equal to “*a“?
why isn’t *a equal to *ptr?

Answer 1

Why is a equal to *a?

Since you cannot print an array, a is implicitly converted from int[10][10] to int(*)[10]. So what actually gets printed instead of a is a pointer to the first line of a.

*a is the first line of the array, and that in turn gets converted to a pointer to the first element.

Since an array has the same address as its first element, you get the same value twice.