Compilare: main.cpp: In member function 'Mat9& Mat9::operator*(Mat9&)': main.cpp:44:8: warning: reference to local variable 'res' returned [-Wreturn-local-addr] Mat9 res; ^~~ main.cpp: In function 'void solve()': main.cpp:64:17: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &A); ^ main.cpp:65:17: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &B); ^ main.cpp:66:17: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &C); ^ main.cpp:67:17: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &i); ^ main.cpp: In function 'int main()': main.cpp:104:34: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("abcacm.in", "r", stdin); ^ main.cpp:105:36: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("abcacm.out", "w", stdout); ^ main.cpp:108:17: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &t); ^