View Compilation Error

0_0_19901822_26441.cpp: In function 'int main()':
0_0_19901822_26441.cpp:3:40: error: 'memset' was not declared in this scope
 #define mem(x,y) memset(x, y, sizeof(x))
                                        ^
0_0_19901822_26441.cpp:18:1: note: in expansion of macro 'mem'
 mem(f, 0);
 ^