Language: C++

#include<bits/stdc++.h>
using namespace std;

int main(){
 int a,b,aa,bb; cin >> a >> b >> aa >> bb;
 int x = aa - a;
 int y = bb - b;
  if(x<0){
    signx = -1;
  }
  else{
    signx = 1;
  }
  
  if(y<0){
    signy = -1;
  }
  else{
    signy = 1
  }
  
  int countx,county = 0,0;
  while(x!=0){
    if(x<0){
      cout << 'R';
      x++;
    }
    else{
      cout << 'L';
      x--;
    }
    countx++;
  }
  while(y!=0){
    if(y<0){
      cout << 'U';
      y++;
    }
    else{
      cout << 'D';
      y--;
    }
    county++;
  }
  
  if(signx == 1){
    x += countx;
  }
  else{
    x -= countx;
  }
  
  if(signy == 1){
    y += county;
  }
  else{
    y -= county;
  }
  
  while(x!=0){
    if(x<0){
      cout << 'L';
      x++;
    }
    else{
      cout << 'R';
      x--;
    }
    countx++;
  }
  while(y!=0){
    if(y<0){
      cout << 'D';
      y++;
    }
    else{
      cout << 'U';
      y--;
    }
    county++;
  }
  
    
  if(signx == 1){
    x += countx;
  }
  else{
    x -= countx;
  }
  
  if(signy == 1){
    y += county;
  }
  else{
    y -= county;
  }
  
  if(signx == 1){
    cout << 'L';
  }
  else{
    cout << 'R';
  }
  if(signy == 1){
    cout << 'U';
  }
  else{
    cout << 'D';
  }
  
  while(x!=0){
    if(x<0){
      cout << 'R';
      x++;
    }
    else{
      cout << 'L';
      x--;
    }
    countx++;
  }
  while(y!=0){
    if(y<0){
      cout << 'U';
      y++;
    }
    else{
      cout << 'D';
      y--;
    }
    county++;
  }
  
  if(signx == 1){
    x += countx;
  }
  else{
    x -= countx;
  }
  
  if(signy == 1){
    y += county;
  }
  else{
    y -= county;
  }
  
  
  if(signy == 1){
    cout << 'D';
  }
  else{
    cout << 'U';
  }
  if(signx == 1){
    cout << 'R';
  }
  else{
    cout << 'L';
  }
  
  if(signy == 1){
    cout << 'D';
  }
  else{
    cout << 'U';
  }
  if(signx == 1){
    cout << 'R';
  }
  else{
    cout << 'L';
  }
  
  
   while(x!=0){
    if(x<0){
      cout << 'L';
      x++;
    }
    else{
      cout << 'R';
      x--;
    }
    countx++;
  }
  while(y!=0){
    if(y<0){
      cout << 'D';
      y++;
    }
    else{
      cout << 'U';
      y--;
    }
    county++;
  }
  
  if(signx == 1){
    cout << 'L';
  }
  else{
    cout << 'R';
  }
  if(signy == 1){
    cout << 'U';
  }
  else{
    cout << 'D';
  }
  
  
}

Compiler output:
a.cc: In function 'int main()':
a.cc:9:5: error: 'signx' was not declared in this scope
    9 |     signx = -1;
      |     ^~~~~
a.cc:12:5: error: 'signx' was not declared in this scope
   12 |     signx = 1;
      |     ^~~~~
a.cc:16:5: error: 'signy' was not declared in this scope
   16 |     signy = -1;
      |     ^~~~~
a.cc:19:5: error: 'signy' was not declared in this scope
   19 |     signy = 1
      |     ^~~~~
a.cc:22:25: error: expected unqualified-id before numeric constant
   22 |   int countx,county = 0,0;
      |                         ^
a.cc:46:6: error: 'signx' was not declared in this scope
   46 |   if(signx == 1){
      |      ^~~~~
a.cc:53:6: error: 'signy' was not declared in this scope
   53 |   if(signy == 1){
      |      ^~~~~
a.cc:84:6: error: 'signx' was not declared in this scope
   84 |   if(signx == 1){
      |      ^~~~~
a.cc:91:6: error: 'signy' was not declared in this scope
   91 |   if(signy == 1){
      |      ^~~~~
a.cc:98:6: error: 'signx' was not declared in this scope
   98 |   if(signx == 1){
      |      ^~~~~
a.cc:104:6: error: 'signy' was not declared in this scope
  104 |   if(signy == 1){
      |      ^~~~~
a.cc:134:6: error: 'signx' was not declared in this scope
  134 |   if(signx == 1){
      |      ^~~~~
a.cc:141:6: error: 'signy' was not declared in this scope
  141 |   if(signy == 1){
      |      ^~~~~
a.cc:149:6: error: 'signy' was not declared in this scope
  149 |   if(signy == 1){
      |      ^~~~~
a.cc:155:6: error: 'signx' was not declared in this scope
  155 |   if(signx == 1){
      |      ^~~~~
a.cc:162:6: error: 'signy' was not declared in this scope
  162 |   if(signy == 1){
      |      ^~~~~
a.cc:168:6: error: 'signx' was not declared in this scope
  168 |   if(signx == 1){
      |      ^~~~~
a.cc:199:6: error: 'signx' was not declared in this scope
  199 |   if(signx == 1){
      |      ^~~~~
a.cc:205:6: error: 'signy' was not declared in this scope
  205 |   if(signy == 1){
      |      ^~~~~