Compilare: user.cpp: In function ‘int main()’: user.cpp:42:13: warning: unused variable ‘nr1’ [-Wunused-variable] int n , nr1,nr2,i,s=0; ^ user.cpp:42:17: warning: unused variable ‘nr2’ [-Wunused-variable] int n , nr1,nr2,i,s=0; ^ user.cpp: In function ‘int r(int, int)’: user.cpp:37:1: warning: control reaches end of non-void function [-Wreturn-type] } ^ user.cpp: In function ‘int main()’: user.cpp:40:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("perechi.in","r",stdin); ^ user.cpp:41:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("perechi.out","w",stdout); ^ user.cpp:43:19: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&n); ^