Compilare: user.cpp: In function ‘int main()’: user.cpp:63:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0;i<s.size();++i) printf("%d\n",s[i]); ^ user.cpp:50:31: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("nc.in","r",stdin); ^ user.cpp:51:33: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("nc.out","w",stdout); ^ user.cpp:53:13: warning: ignoring return value of ‘char* gets(char*)’, declared with attribute warn_unused_result [-Wunused-result] gets(tx);ind=0;Z=strlen(tx); ^ user.cpp: In function ‘void solve()’: user.cpp:28:22: warning: ignoring return value of ‘char* gets(char*)’, declared with attribute warn_unused_result [-Wunused-result] gets(tx); ^ user.cpp:40:22: warning: ignoring return value of ‘char* gets(char*)’, declared with attribute warn_unused_result [-Wunused-result] gets(tx); ^ /tmp/ccxhNQSc.o: In function `main': user.cpp:(.text.startup+0x56): warning: the `gets' function is dangerous and should not be used.