View Compilation Error

0_0_21600800_18106.cpp:75:16: error: stray '#' in program
   Extend(s[i]-'a');
                ^
0_0_21600800_18106.cpp:75:22: error: stray '#' in program
   Extend(s[i]-'a');
                      ^
0_0_21600800_18106.cpp: In function 'int main()':
0_0_21600800_18106.cpp:75:17: error: lvalue required as unary '&' operand
   Extend(s[i]-'a');
                 ^
0_0_21600800_18106.cpp:75:20: error: 'a' was not declared in this scope
   Extend(s[i]-'a');
                    ^
0_0_21600800_18106.cpp:75:26: error: expected primary-expression before ')' token
   Extend(s[i]-'a');
                          ^