/in/foo.cc: In function 'int main()':
/in/foo.cc:9:27: error: 'strlen' was not declared in this scope
   for (i = 0; i < strlen(a); i++)
                           ^
/in/foo.cc:22:27: error: 'strlen' was not declared in this scope
   for (i = 0; i < strlen(a); i++)
                           ^