View Compilation Error

0_0_37804862_10517.cpp: In function 'void Build(char*, int)':
0_0_37804862_10517.cpp:25:23: error: 'x' was not declared in this scope
         if(!tree[now][x]){
                       ^
0_0_37804862_10517.cpp:28:23: error: 'x' was not declared in this scope
         now=tree[now][x];
                       ^