Compilare: user.cpp: In function ‘void ReadData()’: user.cpp:24:18: warning: unused variable ‘j’ [-Wunused-variable] for (int i = 1, j; i <= N; i++) ^ user.cpp: In function ‘void WriteData()’: user.cpp:69:17: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (L(i,j) > M) ^ user.cpp:85:41: warning: ‘X’ is used uninitialized in this function [-Wuninitialized] fprintf(f, "%d %d %d %d", X, Y, XX, YY); ^ user.cpp:85:41: warning: ‘Y’ is used uninitialized in this function [-Wuninitialized]