Compilare: user.cpp: In function ‘int main()’: user.cpp:57:29: warning: unused variable ‘l’ [-Wunused-variable] int nrlin, nrcol, i, j, l, x, y, a, b, k; ^ user.cpp:57:32: warning: unused variable ‘x’ [-Wunused-variable] int nrlin, nrcol, i, j, l, x, y, a, b, k; ^ user.cpp:57:35: warning: unused variable ‘y’ [-Wunused-variable] int nrlin, nrcol, i, j, l, x, y, a, b, k; ^ user.cpp:57:38: warning: unused variable ‘a’ [-Wunused-variable] int nrlin, nrcol, i, j, l, x, y, a, b, k; ^ user.cpp:57:41: warning: unused variable ‘b’ [-Wunused-variable] int nrlin, nrcol, i, j, l, x, y, a, b, k; ^ user.cpp: In function ‘char nextch()’: user.cpp:12:37: 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); ^