View Compilation Error

0_0_18228039_21323.cpp: In function 'int bfs(int, int, int, int)':
0_0_18228039_21323.cpp:26:10: error: 'fx' was not declared in this scope
     flag[fx][fy] = true;
          ^
0_0_18228039_21323.cpp:26:14: error: 'fy' was not declared in this scope
     flag[fx][fy] = true;
              ^