0_0_26994376_20748.cpp: In function 'void init()': 0_0_26994376_20748.cpp:10:38: error: 'memset' was not declared in this scope #define mem(a,b) memset(a,b,sizeof(a)) ^ 0_0_26994376_20748.cpp:16:2: note: in expansion of macro 'mem' mem(tree, 0); ^