Compilare: user.cpp: In function ‘int lungimemax()’: user.cpp:11:30: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=1;i<exp.length();i+=2) ^ user.cpp: In function ‘void eliminare()’: user.cpp:31:30: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=2;i<exp.length();i++) ^ user.cpp: In function ‘int main()’: user.cpp:47:36: 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:48:38: 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:49:22: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d\n", &p); ^