Compilare: user.cpp: In function ‘int main()’: user.cpp:32:34: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("alpin.in","r",stdin); ^ user.cpp:33:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("alpin.out","w",stdout); ^ user.cpp:37:19: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&n); ^ user.cpp:42:49: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] for(j=1;j<=n;j++) scanf("%d",&mat[i][j]); ^ user.cpp:35:26: warning: ‘col’ may be used uninitialized in this function [-Wmaybe-uninitialized] int n,i,j,maxx=0,lin,col; ^ user.cpp:35:22: warning: ‘lin’ may be used uninitialized in this function [-Wmaybe-uninitialized] int n,i,j,maxx=0,lin,col; ^