Compilare: user.cpp: In function ‘int main()’: user.cpp:25:25: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while(h<strlen(a)) ^ user.cpp:28:51: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while(a[h]>='0'&&a[h]<='9'&&h<strlen(a)) ^