View Compilation Error

0_0_32266512_24016.cpp: In function 'int main()':
0_0_32266512_24016.cpp:31:23: error: 'memset' was not declared in this scope
   memset(a,0,sizeof(a));
                       ^
0_0_32266512_24016.cpp:33:25: error: 'strlen' was not declared in this scope
   for(int i=0;i<strlen(s);i++)
                         ^