View Compilation Error

0_0_19436236_16921.cpp: In member function 'void TRIE::insert(int)':
0_0_19436236_16921.cpp:50:17: error: 'strlen' was not declared in this scope
 int len=strlen(s),t=0;
                 ^
0_0_19436236_16921.cpp:55:7: error: 't' was not declared in this scope
 if(tr[t].p[s[x]-'a']){
       ^