View Compilation Error

0_0_19834006_13342.cpp: In function 'int main()':
0_0_19834006_13342.cpp:12:36: error: 'memset' was not declared in this scope
 #define mset(a) memset(a,0,sizeof a)
                                    ^
0_0_19834006_13342.cpp:75:9: note: in expansion of macro 'mset'
         mset(x);
         ^