Help me please!

Question

So here is the code
#include <iostream>
using namespace std;
int main()
{
int Number[]={2,4,8,10};
int *ptr=Number;
for(int C=0;C<3;C++)
{cout<<*ptr<<"@";
ptr++;
}
{
cout<<endl;
for(int C=0;C<4;C++)
{(*ptr)*=2;
cout<<Number[C]<<"#";
--ptr;
}}
cout<<endl;
return 0;
}

Please somebody explain me the work of that --p. I understood the p++ for increment but I'm unable to relate the same with --p. When I run it the output comes out to be 2#4#8#16#20# for --p part. Please explain it to me with the help of the given output.
Thank you

Answer 1

p++ increments at the end of the loop, p-- would decrement at the end of the loop. Placing the -- symbol before p, such as --p, means that before the loop takes place, p is decremented by 1.