Compilare: main.cpp: In function 'int main()': main.cpp:8:16: warning: unused variable 'ans' [-Wunused-variable] double a,b,ans,d; ^~~ main.cpp:6:33: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("nasa.in","r",stdin); ^ main.cpp:7:35: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("nasa.out","w",stdout); ^ main.cpp:10:26: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%lf%lf",&a,&b); ^