Compilare: user.cpp: In function ‘long long int create()’: user.cpp:27:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<strlen(p);++i){ ^ user.cpp: In function ‘void decode(long long int&)’: user.cpp:39:28: warning: passing NULL to non-pointer argument 2 of ‘void* memset(void*, int, size_t)’ [-Wconversion-null] memset(p,NULL,sizeof(p)); ^ user.cpp: In function ‘int main()’: user.cpp:61:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j=0;j<strlen(p);++j) ^