Compilare: user.cpp: In function ‘long long int calcul(long long int, long long int)’: user.cpp:9:33: warning: value computed is not used [-Wunused-value] if (b<0) calcul(1/a,b*(-1))%MOD; ^ user.cpp:14:2: warning: control reaches end of non-void function [-Wreturn-type] } ^ user.cpp: In function ‘int main()’: user.cpp:18:40: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("classictask.in","r",stdin); ^ user.cpp:19:42: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("classictask.out","w",stdout); ^ user.cpp:21:42: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%lld %lld %lld", &a, &b, &MOD); ^