Compilare: user.cpp: In function ‘int main()’: user.cpp:58:32: warning: variable ‘x’ set but not used [-Wunused-but-set-variable] int nrlin, nrcol, i, j, l, x, y, a, b, k; ^ user.cpp:58:35: warning: variable ‘y’ set but not used [-Wunused-but-set-variable] int nrlin, nrcol, i, j, l, x, y, a, b, k; ^ user.cpp: In function ‘char nextch()’: user.cpp:13:37: warning: ignoring return value of ‘size_t fread(void*, size_t, size_t, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] fread(buf, BUF_SIZE, 1, fin); ^