add shift(incomplete)

include<iostream>
#include<conio.h>

using namespace std;
int a[4],multiplicand[4],i,carry=0,sum;
void display();
void getdata()
{
     cout<<"enter tbinary multiplicand:";
                  for(i=0;i<4;i++)
                  cin>>multiplicand[i];
                  cout<<"enter mulplier:";
                  for(i=5;i<9;i++)
                  cin>>a[i];
                 
                  for(i=0;i<5;i++)
                  a[i]=0;
                 
                  cout<<"intial stat\n multiplier:";
                  for(i=1;i<9;i++)
                  cout<<a[i];
                  cout<<"\nmultiplicand:0000";
                  for(i=0;i<4;i++)
                  cout<<" "<<multiplicand[i];
                  }
                  int add(int p1,int p2)
                  {
                      if(p1==1&&p2==1)
                      {
                                      if(carry==0)
                                      for(i=8;i>0;i--)
                                      a[i]=a[i-1];
                                      cout<<"\n\n";
                                      a[0]=0;
                                      display();
                                      }
                                      }
                  void display()
                  {
                       for(i=0;i<9;i++)
                       cout<<" "<<a[i];
                       }
                       int main()
                       {
                           
                           
                            getdata();
                            add();
                            display();
                            getch();
                            return 0;
                            }