View Compilation Error

0_0_34123069_21572.cpp: In function 'int time(char*)':
0_0_34123069_21572.cpp:16:23: error: 'strlen' was not declared in this scope
     int len = strlen(a);
                       ^
0_0_34123069_21572.cpp: In function 'int main()':
0_0_34123069_21572.cpp:44:31: error: 'strcmp' was not declared in this scope
             if (strcmp(tt, "#") == 0) break;
                               ^