Compilare: main.cpp: In function 'int add(int)': main.cpp:16:14: warning: no return statement in function returning non-void [-Wreturn-type] st.insert(x);} ^ main.cpp: In function 'int main()': main.cpp:87:23: warning: format '%d' expects argument of type 'int', but argument 2 has type 'std::set<int>::size_type {aka long unsigned int}' [-Wformat=] printf("%d ",st.size()); ^ main.cpp:19:31: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("coduri.in","r",stdin); ^ main.cpp:20:33: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("coduri.out","w",stdout); ^ main.cpp:22:17: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d\n",&n); ^ main.cpp:24:22: warning: ignoring return value of 'char* fgets(char*, int, FILE*)', declared with attribute warn_unused_result [-Wunused-result] fgets(ch+1,103,stdin); ^