Compilare: user.cpp: In function ‘int main()’: user.cpp:39:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 1; i < v.size(); i++) ^ user.cpp:17:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("zimeria.in", "r", stdin); ^ user.cpp:18:40: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("zimeria.out", "w", stdout); ^ user.cpp:22:29: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d\n", &op, &N); ^ user.cpp:23:16: warning: ignoring return value of ‘char* gets(char*)’, declared with attribute warn_unused_result [-Wunused-result] gets(s + 1); ^ user.cpp:29:20: warning: ignoring return value of ‘char* gets(char*)’, declared with attribute warn_unused_result [-Wunused-result] gets(s + 1); ^ /tmp/ccTrqETT.o: In function `main': user.cpp:(.text.startup+0x84): warning: the `gets' function is dangerous and should not be used.