View Compilation Error

0_0_38247439_1638.cpp: In function 'int main()':
0_0_38247439_1638.cpp:3:37: error: 'memset' was not declared in this scope
 #define met(a,b)memset(a,b,sizeof(a)) 
                                     ^
0_0_38247439_1638.cpp:11:3: note: in expansion of macro 'met'
 { met(c1,0);met(c2,0); for(int i=0;i<n;i++)
   ^