Christmas Tree code implemented in C++

#include <cstdlib>
#include <iostream>
#include <iomanip.h>
using namespace std;

int main(int argc, char *argv[])
{
   
    char c='*';
    int size;
    cout<<"enter size\n";
    cin>>size;
    int a=10;
    int k=0;
    int i=0;
    while(k<3){
    for(;i<size;i=i+2)
    {
           cout<<setw(a);
            for(int j=0;j<=i;j++)
            cout<<c;
            cout<<endl;
            a--;
            }
            a=10;
           
            k++;
            a=a-k;
            i=k;
            }
           
   
   
   
   
    system("PAUSE");
    return EXIT_SUCCESS;
}