0_0_29910207_4614.cpp: In function 'int main()': 0_0_29910207_4614.cpp:2:36: error: 'memset' was not declared in this scope #define mst(x) memset(x,0,sizeof(x)) ^ 0_0_29910207_4614.cpp:47:9: note: in expansion of macro 'mst' mst(stree); ^