Compilare: user.cpp: In function ‘int main()’: user.cpp:46:34: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("concert2.in","r",stdin); ^ user.cpp:47:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("concert2.out","w",stdout); ^ user.cpp:51:36: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d%d%d",&n,&k1,&k2,&x); ^ user.cpp:54:21: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] { scanf("%d",&x); ^ user.cpp:70:6: warning: ‘x’ may be used uninitialized in this function [-Wmaybe-uninitialized] if(s.peek()!=x)s.push(x); ^ user.cpp:55:27: warning: ‘x’ may be used uninitialized in this function [-Wmaybe-uninitialized] if(((isascending)&&(x>s.peek()))||((isascending==0)&&(x<s.peek()))) ^ user.cpp:55:61: warning: ‘x’ may be used uninitialized in this function [-Wmaybe-uninitialized] if(((isascending)&&(x>s.peek()))||((isascending==0)&&(x<s.peek()))) ^ user.cpp:67:58: warning: ‘x’ may be used uninitialized in this function [-Wmaybe-uninitialized] if(((isascending)&&(x<s.peek()))||((isascending==0)&&(x>s.peek()))) ^ user.cpp:67:24: warning: ‘x’ may be used uninitialized in this function [-Wmaybe-uninitialized] if(((isascending)&&(x<s.peek()))||((isascending==0)&&(x>s.peek()))) ^