Compilare: user.cpp: In function ‘int main(int, const char**)’: user.cpp:88:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0; i < ANS.size(); ++i) ^ user.cpp:25:28: warning: unused variable ‘l’ [-Wunused-variable] int N = (int)strlen(S),l=1,secv=0; ^ user.cpp:25:32: warning: unused variable ‘secv’ [-Wunused-variable] int N = (int)strlen(S),l=1,secv=0; ^ user.cpp:17:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen ("charlie.in","r",stdin); ^ user.cpp:18:39: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen ("charlie.out","w",stdout); ^ user.cpp:21:21: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d\n",&C); ^ user.cpp:23:12: warning: ignoring return value of ‘char* gets(char*)’, declared with attribute warn_unused_result [-Wunused-result] gets(S); ^ /tmp/ccOIHGjp.o: In function `main': user.cpp:(.text.startup+0x6a): warning: the `gets' function is dangerous and should not be used.