High pow function

#include <string.h>
#include <iostream>
using namespace std;
string pow(unsigned int x, unsigned int y,unsigned int memsize)
{
unsigned char *memory = (char*)malloc(memsize);
memset(&memory[0], 0, memsize);
memory[0] = 1;
string pow;char buf[2];
bool zeros=true;
int i, in;
for (i =0; i<y;  i++)
    {
    for (in=0; in<y; in++)
            memory[in]*=x;
    for (in=0; in<y-1; in++)
        if(memory[in]>9)
        {
        memory[in+1] += memory[in]/10;
        memory[in] %=10;
        }
    }
    for (i=y-1; i>=0; i--)
    {
    if (zeros) if (memory[i] == 0) continue;
    else    {
    in = i;
    zeros = false;
            }
    itoa(memory[i], &buf[0], 10);
    pow+=buf;
    }
free(memory);
return pow;
}

int main()
{
int x = 1, y;
cout<<"x^y"<<endl;
while (x)
    {
    cout<<"x: "; cin>>x;
    cout<<"y: "; cin>>y;
    string result = pow(x,y,8000);
    cout<<result<<endl;
    }
return 0;
}