Compilare: user.cpp: In function ‘int main()’: user.cpp:39:12: warning: unused variable ‘step’ [-Wunused-variable] int i, step, l,a, b, aa, bb; ^ user.cpp:42:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen ("farey.in", "r", stdin); ^ user.cpp:43:39: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen ("farey.out", "w", stdout); ^ user.cpp:45:27: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf ("%d%d", &n, &k); ^ user.cpp: In function ‘int solve(double)’: user.cpp:29:26: warning: ‘bb’ may be used uninitialized in this function [-Wmaybe-uninitialized] ciur [i] = a * i / b; // c < a * i / b ^ user.cpp: In function ‘int main()’: user.cpp:61:15: warning: ‘ans’ may be used uninitialized in this function [-Wmaybe-uninitialized] a = b * ans; ^