Compilare: user.cpp: In function ‘void print(std::string)’: user.cpp:63:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (i=0;i<s.size();i++) printf("%c",s[i]); ^ user.cpp: In function ‘int main()’: user.cpp:89:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (b=1;b<=se.size();b++) ^ user.cpp:67:28: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("sub.in","r",stdin); ^ user.cpp:68:30: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("sub.out","w",stdout); ^ user.cpp:69:18: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d\n",&n1); ^ user.cpp:70:10: warning: ignoring return value of ‘char* gets(char*)’, declared with attribute warn_unused_result [-Wunused-result] gets(s+1); n=strlen(s+1); root=new trie; ^ user.cpp:73:14: warning: ignoring return value of ‘char* gets(char*)’, declared with attribute warn_unused_result [-Wunused-result] gets(s+1); n=strlen(s+1); b=i; ^ user.cpp:79:18: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d\n",&n1); ^ user.cpp:81:12: warning: ignoring return value of ‘char* gets(char*)’, declared with attribute warn_unused_result [-Wunused-result] gets(s); ss=s; ^ /tmp/ccJfMNRb.o: In function `main': user.cpp:(.text.startup+0x6a): warning: the `gets' function is dangerous and should not be used.