View Compilation Error

0_0_36686765_18035.cpp: In function 'long long int find(long long int)':
0_0_36686765_18035.cpp:29:9: error: 'pre' was not declared in this scope
     if (pre[x] != x) pre[x] = find(pre[x]);
         ^
0_0_36686765_18035.cpp:30:12: error: 'pre' was not declared in this scope
     return pre[x];
            ^
0_0_36686765_18035.cpp: In function 'int main()':
0_0_36686765_18035.cpp:39:25: error: 'n' was not declared in this scope
         scanf("%d%d%d",&n,&m,&q);
                         ^
0_0_36686765_18035.cpp:39:28: error: 'm' was not declared in this scope
         scanf("%d%d%d",&n,&m,&q);
                            ^
0_0_36686765_18035.cpp:39:31: error: 'q' was not declared in this scope
         scanf("%d%d%d",&n,&m,&q);
                               ^
0_0_36686765_18035.cpp:84:40: error: 'cout' was not declared in this scope
         for (int i = 1; i <= q; i ++ ) cout << ans[i] << endl;        
                                        ^
0_0_36686765_18035.cpp:84:58: error: 'endl' was not declared in this scope
         for (int i = 1; i <= q; i ++ ) cout << ans[i] << endl;        
                                                          ^