divide.cpp:42:1: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
42 | main() {
| ^~~~
divide.cpp: In function 'int main()':
divide.cpp:4:48: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
4 | #define file(s) if (fopen(s".in", "r")) freopen(s".in", "r", stdin), freopen(s".out", "w", stdout)
| ~~~~~~~^~~~~~~~~~~~~~~~~~~~
divide.cpp:43:2: note: in expansion of macro 'file'
43 | file("divide");
| ^~~~
divide.cpp:4:77: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
4 | #define file(s) if (fopen(s".in", "r")) freopen(s".in", "r", stdin), freopen(s".out", "w", stdout)
| ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~
divide.cpp:43:2: note: in expansion of macro 'file'
43 | file("divide");
| ^~~~