Compilare: user.cpp: In function ‘int main()’: user.cpp:27:46: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(f, "%lf %lf %lf %d", &A, &B, &C, &N); ^ user.cpp:29:30: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(f, "%lf", &val[i]); ^ user.cpp:44:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("iopds.out", "w", stdout); ^