View Compilation Error

0_0_26048503_3948.cpp: In function 'void bfs()':
0_0_26048503_3948.cpp:43:21: error: 'f0' was not declared in this scope
                 vis[f0][x0][y0]=1;//printf("x0=%d y0=%d %d %d\n",x0,y0,c.sum,vis[x0][y0]);
                     ^
0_0_26048503_3948.cpp:43:25: error: 'x0' was not declared in this scope
                 vis[f0][x0][y0]=1;//printf("x0=%d y0=%d %d %d\n",x0,y0,c.sum,vis[x0][y0]);
                         ^
0_0_26048503_3948.cpp:43:29: error: 'y0' was not declared in this scope
                 vis[f0][x0][y0]=1;//printf("x0=%d y0=%d %d %d\n",x0,y0,c.sum,vis[x0][y0]);
                             ^