Compilare: user.cpp: In function ‘int main()’: user.cpp:41:24: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 1; i<=k; i++) ^ user.cpp:12:27: warning: ‘aux’ may be used uninitialized in this function [-Wmaybe-uninitialized] return (x == '!' || x == '.' || x == '?'); ^ user.cpp:19:12: note: ‘aux’ was declared here char x,aux; ^