Compilare: user.cpp: In function ‘int main()’: user.cpp:9:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("submatrix.in","r",stdin); ^ user.cpp:10:40: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("submatrix.out","w",stdout);\ ^ user.cpp:39:64: warning: ‘jmax2’ may be used uninitialized in this function [-Wmaybe-uninitialized] cout<<Smax<<endl<<imax1<<" "<<jmax1<<" "<<imax2<<" "<<jmax2; ^ user.cpp:39:54: warning: ‘imax2’ may be used uninitialized in this function [-Wmaybe-uninitialized] cout<<Smax<<endl<<imax1<<" "<<jmax1<<" "<<imax2<<" "<<jmax2; ^~~ user.cpp:39:42: warning: ‘jmax1’ may be used uninitialized in this function [-Wmaybe-uninitialized] cout<<Smax<<endl<<imax1<<" "<<jmax1<<" "<<imax2<<" "<<jmax2; ^~~ user.cpp:39:30: warning: ‘imax1’ may be used uninitialized in this function [-Wmaybe-uninitialized] cout<<Smax<<endl<<imax1<<" "<<jmax1<<" "<<imax2<<" "<<jmax2; ^~~