Compilare: user.cpp: In function ‘int main()’: user.cpp:24:25: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (i=2; i<strlen(a); i++) ^ user.cpp:63:25: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (i=2; i<strlen(a); i++) ^ user.cpp:15:32: 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:16:34: 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:17:16: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%ld",&p); ^ user.cpp:18:14: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%s",a); ^