Compilare: user.cpp: In function ‘void bktr()’: user.cpp:26:37: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<stiva[1].size();++i) ^ user.cpp: In function ‘int main()’: user.cpp:69:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("immortal.in","r",stdin); ^ user.cpp:70:39: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("immortal.out","w",stdout); ^ user.cpp:71:31: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d %d",&n,&m,&k); ^ user.cpp:85:29: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d",&x,&y); ^