Compilare: user.cpp: In function ‘int main()’: user.cpp:18:24: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=1;i<=n;++i) ^ user.cpp:19:28: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j=1;j<=n;++j) ^ user.cpp:21:24: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=1;i<=n;++i) ^ user.cpp:22:28: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j=1;j<=n;++j) ^ user.cpp:35:24: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=m;i<=n;++i) ^ user.cpp:36:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j=m;j<=n;++j) ^ user.cpp:55:24: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=m;i<=n;++i) ^ user.cpp:56:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j=m;j<=n;++j) ^