View Compilation Error

0_0_13575325_24099.cpp: In function 'int main()':
0_0_13575325_24099.cpp:12:23: error: 'memset' was not declared in this scope
   memset(a,0,sizeof(a));
                       ^
0_0_13575325_24099.cpp:15:17: error: 'sort' was not declared in this scope
   sort(a+1,a+1+n); 
                 ^