Compilare: user.cpp: In function ‘int main()’: user.cpp:58:26: warning: converting to non-pointer type ‘char’ from NULL [-Wconversion-null] mat[l][r]=NULL; ^ user.cpp:15:8: warning: variable ‘ir’ set but not used [-Wunused-but-set-variable] int ir,i,j,n,nr,ne,v[1000],l,r,maxi,c; ^ user.cpp:15:20: warning: unused variable ‘ne’ [-Wunused-variable] int ir,i,j,n,nr,ne,v[1000],l,r,maxi,c; ^ user.cpp:15:35: warning: variable ‘maxi’ set but not used [-Wunused-but-set-variable] int ir,i,j,n,nr,ne,v[1000],l,r,maxi,c; ^ user.cpp:15:40: warning: unused variable ‘c’ [-Wunused-variable] int ir,i,j,n,nr,ne,v[1000],l,r,maxi,c; ^