Compilare: user.cpp: In function ‘int main()’: user.cpp:64:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while(i < strlen(S)){ ^ user.cpp:92:30: warning: format ‘%ld’ expects argument of type ‘long int’, but argument 2 has type ‘std::vector<long int>::size_type {aka unsigned int}’ [-Wformat=] printf("%ld\n",Ans.size()); ^ user.cpp:93:24: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0;i<Ans.size();i++) W[Ans[i]].write(); ^ user.cpp:59:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("mesaje.in","r",stdin); ^ user.cpp:60:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("mesaje.out","w",stdout); ^ user.cpp:62:19: warning: ignoring return value of ‘char* gets(char*)’, declared with attribute warn_unused_result [-Wunused-result] n = 0; gets(S); ^ user.cpp:79:26: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%s",S); ^ /tmp/ccXqC1DC.o: In function `main': user.cpp:(.text.startup+0x60): warning: the `gets' function is dangerous and should not be used.