Compilare: user.cpp: In function ‘int main()’: user.cpp:89:29: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (it = 1;it < V.size();it++) ^ user.cpp:93:29: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (e >= V.size() - it) ^ user.cpp:101:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (it == V.size()) ^ user.cpp:29:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("robot3.in","r",stdin); ^ user.cpp:30:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("robot3.out","w",stdout); ^ user.cpp:34:38: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d %d %d",&N,&M,&r,&c); ^ user.cpp:45:31: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%c%c",&Op,&Op); ^ user.cpp:75:27: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&X); ^