Compilare: user.cpp: In function ‘int main()’: user.cpp:22:27: warning: NULL used in arithmetic [-Wpointer-arith] for(i=0;v[i]!=NULL;++i) ^ user.cpp:12:34: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("queue.in","r",stdin); ^ user.cpp:13:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("queue.out","w",stdout); ^ user.cpp:14:21: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d\n",&m); ^ user.cpp:19:16: warning: ignoring return value of ‘char* gets(char*)’, declared with attribute warn_unused_result [-Wunused-result] gets(v); ^ /tmp/ccrLlDFn.o: In function `main': user.cpp:(.text.startup+0xae): warning: the `gets' function is dangerous and should not be used.