Pointer to shift array C++

Question

Im trying to shift my array left as efficiently as possible. Im using pointers now, and im having trouble assigning the values back into my array:

void stack::rotate(int nRotations)
{
   if ( count <= 1 ) return;

   int *intFrontPtr = &items[top+1].n;
   int *intBackPtr  = &items[count-1].n;
   int temp = 0;

   for (int shift = 0; nRotations != 0 ;)
   {
        if ( nRotations > 0 ) // we rotate left
        {  
             temp = *++intFrontPtr; // give temp the value
             items[++shift].n = temp; // debug shows success
             if ( shift == count ) // dont overrun array
             {
                 temp = *intBackPtr;
                 items[count-1].n = temp;
                 shift = 0; // reset for another rotation
                 nRotations--; // decrement we have reached the end
             }
        }

    } 
}

You'd probably get more help if you accepted answers more than just 21% of the time. — cdiggins
– cdiggins, Commented Nov 1, 2009 at 4:23
And also if he did not just repeated the same question over and over... — Matthieu M.
– Matthieu M., Commented Nov 1, 2009 at 14:03
Too much is not given to answer this... For example, where is "top" defined... What is "n"? — dicroce
– dicroce, Commented Nov 1, 2009 at 16:49

rlbond · Accepted Answer · 2009-11-01 03:50:21Z

4

c++ has a function built in in <algorithm>. Just call std::rotate(front_ptr, front_ptr + N, back_ptr);

answered Nov 1, 2009 at 3:50

rlbond

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1 Comment

user40120 Over a year ago

referring to the items address might be the problem?

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