art.cpp: In function 'int main(int, char**)':
art.cpp:16:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
16 | freopen(".inp", "r", stdin);
| ~~~~~~~^~~~~~~~~~~~~~~~~~~~
art.cpp:17:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
17 | freopen(".out", "w", stdout);
| ~~~~~~~^~~~~~~~~~~~~~~~~~~~~
art.cpp:21:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
21 | freopen("test.inp", "r", stdin);
| ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~