View Compilation Error

0_0_14608067_622.cpp: In function 'int main()':
0_0_14608067_622.cpp:13:20: error: 'strlen' was not declared in this scope
   int ia = strlen(a);
                    ^
0_0_14608067_622.cpp:18:29: error: 'memset' was not declared in this scope
   memset(sum, 0, sizeof(sum));
                             ^