View Compilation Error

0_0_20848310_30219.cpp: In function 'int main()':
0_0_20848310_30219.cpp:14:25: error: 'memset' was not declared in this scope
   memset(a, 0, sizeof(a));
                         ^
0_0_20848310_30219.cpp:19:3: error: declaration does not declare anything [-fpermissive]
   int;
   ^