View Compilation Error

0_0_19642121_14997.cpp: In function 'void make_fail()':
0_0_19642121_14997.cpp:36:20: error: 'i' was not declared in this scope
     while(!tree[t][i]&&t)
                    ^
0_0_19642121_14997.cpp:39:21: error: 'i' was not declared in this scope
      fail[tree[now][i]]=tree[t][i];
                     ^
0_0_19642121_14997.cpp:40:24: error: 'i' was not declared in this scope
     que.push(tree[now][i]);
                        ^