View Compilation Error

0_0_39667693_8934.cpp: In function 'int main()':
0_0_39667693_8934.cpp:8:17: error: 'x1' was not declared in this scope
    8 |     while (cin>>x1>>y1>>x2>>y2)
      |                 ^~
0_0_39667693_8934.cpp:8:21: error: 'y1' was not declared in this scope
    8 |     while (cin>>x1>>y1>>x2>>y2)
      |                     ^~
0_0_39667693_8934.cpp:8:25: error: 'x2' was not declared in this scope
    8 |     while (cin>>x1>>y1>>x2>>y2)
      |                         ^~
0_0_39667693_8934.cpp:8:29: error: 'y2' was not declared in this scope
    8 |     while (cin>>x1>>y1>>x2>>y2)
      |                             ^~