Compilare: user.cpp: In function ‘int main()’: user.cpp:108:13: warning: unused variable ‘vall’ [-Wunused-variable] int vall=v[midval-1]; ^ user.cpp:82:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("pikachu.in","r",stdin); ^ user.cpp:83:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("pikachu.out","w",stdout); ^ user.cpp:85:24: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d",&n,&k); ^ user.cpp:88:30: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&a[i].val); ^