Main.cpp:23:2: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
23 | main () {
| ^~~~
Main.cpp: In function 'int main()':
Main.cpp:2:60: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
2 | #define file(name) if (fopen (name".inp", "r")) { freopen (name".inp", "r", stdin); freopen (name".out", "w", stdout); }
| ~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
Main.cpp:24:5: note: in expansion of macro 'file'
24 | file("JOI23_HO_T2");
| ^~~~
Main.cpp:2:94: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
2 | #define file(name) if (fopen (name".inp", "r")) { freopen (name".inp", "r", stdin); freopen (name".out", "w", stdout); }
| ~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
Main.cpp:24:5: note: in expansion of macro 'file'
24 | file("JOI23_HO_T2");
| ^~~~