Compilare: user.cpp: In function ‘int main()’: user.cpp:11:16: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=1;i<=n;i++) ^ user.cpp:12:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(j=1;j<=m;j++) ^ user.cpp:14:16: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=1;i<=n;i++) ^ user.cpp:17:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(j=1;j<=m;j++) ^ user.cpp:20:24: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(j=1;j<=m;j++) ^ user.cpp:23:16: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(j=1;j<=m;j++) ^ user.cpp:26:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=1;i<=n;i++) ^ user.cpp:29:24: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=1;i<=n;i++) ^ user.cpp:33:16: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=1;i<=n;i++) ^ user.cpp:34:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(j=1;j<=m;j++) ^