View Compilation Error

0_0_32099132_30193.cpp: In function 'int main()':
0_0_32099132_30193.cpp:105:19: error: 'strlen' was not declared in this scope
  int LL=strlen(s+1),lstans=0;
                   ^
0_0_32099132_30193.cpp:114:15: error: 'lstans' was not declared in this scope
    ch=(ch-'a'+lstans)%26+'a';
               ^
0_0_32099132_30193.cpp:120:11: error: 'lstans' was not declared in this scope
    l=(l-1+lstans)%now+1,r=(r-1+lstans)%now+1;
           ^