View Compilation Error

F:	emp9734277.2655Main.cc: In function 'int main()':
F:	emp9734277.2655Main.cc:12: error: 'scanf' was not declared in this scope
F:	emp9734277.2655Main.cc:13: error: 'memset' was not declared in this scope
F:	emp9734277.2655Main.cc: In function 'bool dfs(int, int, int)':
F:	emp9734277.2655Main.cc:24: error: 'puts' was not declared in this scope
F:	emp9734277.2655Main.cc:26: error: 'puts' was not declared in this scope