DDA ALGORITHRM

#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
typedef pair<ll,ll>pll;
typedef pair<ll,pair<ll,ll>>plll;
#define fastread() (ios_base:: sync_with_stdio(false),cin.tie(NULL));
#define vll(v) v.begin(),v.end()
#define all(x) x.rbegin(),x.rend()
#define min3(a, b, c)   min(a, min(b, c))
#define max3(a, b, c)   max(a, max(b, c))
#define sf(a) scanf("%d",&a)
#define pf(a) printf("%d",a);
#define F first
#define S second
#define in  freopen("input.txt", "r", stdin)
#define out  freopen("output.txt", "w", stdout)
#define minheap int,vector<int>,greater<int>
#define pb push_back
#define eb emplace_back
#define ischar(x)  (('a' <= x && x <= 'z') || ('A' <= x && x <= 'Z'))
#define isvowel(ch) ((ch=='a'||ch=='e'||ch=='i'||ch=='o'||ch=='u')||(ch=='A'|| ch=='E' || ch=='I'|| ch=='O'|| ch=='U'))
#define bug cout<<"BUG"<<endl;
const int Max = 2e6 + 10;
const int Mod = 1e9 + 7;
const double PI  =3.141592653589793238463;
bool compare(const pair<ll,ll> &a, const pair<ll,ll> &b)
{
       return (a.first > b.first);
}
ll lcm(ll a,ll b)
{
    if(a==0 || b==0)return 0;

    return a/__gcd(a,b)*b;
}

void input(ll ara[],ll n)
{
    for(ll i=0; i<n; i++)cin>>ara[i];
}
void print(ll ara[],ll n)
{
    for(ll i=0; i<n; i++)
        cout<<ara[i]<<" ";
    cout<<endl;
}


int main()
{

   fastread();

   ll i,j,n,p,a,sum=0,k,t,c,d,cnt=0,q,l,r,ans=0;

      bool flag=false;

      string str;

      double x1,x2,y1,y2,x,y,b;

      cin>>x1>>y1>>x2>>y2;

      double m=(y2-y1)/(x2-x1);



      b=y1-(m*x1);



      if( abs(m)<=1)
      {
         if(x1>x2)
         {
             swap(x1,x2);
             swap(y1,y2);

         }

         x=x1;
         y=y1;

         while(x<=x2)
         {
             cout<<x<<" "<<round(y)<<endl;



             x++;
             y+=m;

         }
      }
      else
      {

           if(y1>y2)
         {
             swap(x1,x2);
             swap(y1,y2);

         }

         x=x1;
         y=y1;

         while(y<=y2)
         {
             cout<<round(x)<<" "<<y<<endl;

            x+=(1.0/m);
            y++;

         }
      }







      return 0;


}