Compilare: user.cpp: In function ‘int main()’: user.cpp:212:8: warning: unused variable ‘j’ [-Wunused-variable] int i,j,l,x,nr=0; ^ user.cpp:210:30: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("zeap.in","r",stdin); ^ user.cpp:211:32: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("zeap.out","w",stdout); ^ user.cpp:48:3: warning: ‘x’ may be used uninitialized in this function [-Wmaybe-uninitialized] if (val < N->value) ^ user.cpp:212:12: note: ‘x’ was declared here int i,j,l,x,nr=0; ^ /tmp/cc8aU8XE.o: In function `main': user.cpp:(.text.startup+0xa8): warning: the `gets' function is dangerous and should not be used.