Valgrind found both the uninitialized read and write, but it seems that it
only flags the read from uninitialized memory once we print it; it's not clear
whether that bug would still be caught if we were to use the value differently

==16114== Memcheck, a memory error detector.
==16114== Copyright (C) 2002-2005, and GNU GPL'd, by Julian Seward et al.
==16114== Using LibVEX rev 1471, a library for dynamic binary translation.
==16114== Copyright (C) 2004-2005, and GNU GPL'd, by OpenWorks LLP.
==16114== Using valgrind-3.1.0, a dynamic binary instrumentation framework.
==16114== Copyright (C) 2000-2005, and GNU GPL'd, by Julian Seward et al.
==16114== For more details, rerun with: -v
==16114== 
Hello world!
Now reading uninitialized memory
Did you notice? (value was ==16114== Conditional jump or move depends on uninitialised value(s)
==16114==    at 0x40A2F8F: std::ostreambuf_iterator<char, std::char_traits<char> > std::num_put<char, std::ostreambuf_iterator<char, std::char_traits<char> > >::_M_convert_int<long>(std::ostreambuf_iterator<char, std::char_traits<char> >, std::ios_base&, char, long) const (in /usr/lib/libstdc++.so.5.0.7)
==16114==    by 0x40A2BDF: std::num_put<char, std::ostreambuf_iterator<char, std::char_traits<char> > >::do_put(std::ostreambuf_iterator<char, std::char_traits<char> >, std::ios_base&, char, long) const (in /usr/lib/libstdc++.so.5.0.7)
==16114==    by 0x40B86FB: std::ostream::operator<<(long) (in /usr/lib/libstdc++.so.5.0.7)
==16114==    by 0x40B8BEC: std::ostream::operator<<(int) (in /usr/lib/libstdc++.so.5.0.7)
==16114==    by 0x804882A: main (wrong3.cc:12)
==16114== 
==16114== Use of uninitialised value of size 4
==16114==    at 0x40B36D4: (within /usr/lib/libstdc++.so.5.0.7)
==16114==    by 0x40A2FBC: std::ostreambuf_iterator<char, std::char_traits<char> > std::num_put<char, std::ostreambuf_iterator<char, std::char_traits<char> > >::_M_convert_int<long>(std::ostreambuf_iterator<char, std::char_traits<char> >, std::ios_base&, char, long) const (in /usr/lib/libstdc++.so.5.0.7)
==16114==    by 0x40A2BDF: std::num_put<char, std::ostreambuf_iterator<char, std::char_traits<char> > >::do_put(std::ostreambuf_iterator<char, std::char_traits<char> >, std::ios_base&, char, long) const (in /usr/lib/libstdc++.so.5.0.7)
==16114==    by 0x40B86FB: std::ostream::operator<<(long) (in /usr/lib/libstdc++.so.5.0.7)
==16114==    by 0x40B8BEC: std::ostream::operator<<(int) (in /usr/lib/libstdc++.so.5.0.7)
==16114==    by 0x804882A: main (wrong3.cc:12)
==16114== 
==16114== Conditional jump or move depends on uninitialised value(s)
==16114==    at 0x40B36E0: (within /usr/lib/libstdc++.so.5.0.7)
==16114==    by 0x40A2FBC: std::ostreambuf_iterator<char, std::char_traits<char> > std::num_put<char, std::ostreambuf_iterator<char, std::char_traits<char> > >::_M_convert_int<long>(std::ostreambuf_iterator<char, std::char_traits<char> >, std::ios_base&, char, long) const (in /usr/lib/libstdc++.so.5.0.7)
==16114==    by 0x40A2BDF: std::num_put<char, std::ostreambuf_iterator<char, std::char_traits<char> > >::do_put(std::ostreambuf_iterator<char, std::char_traits<char> >, std::ios_base&, char, long) const (in /usr/lib/libstdc++.so.5.0.7)
==16114==    by 0x40B86FB: std::ostream::operator<<(long) (in /usr/lib/libstdc++.so.5.0.7)
==16114==    by 0x40B8BEC: std::ostream::operator<<(int) (in /usr/lib/libstdc++.so.5.0.7)
==16114==    by 0x804882A: main (wrong3.cc:12)
2) 
(No memory leak here)
Now writing to uninitialized pointer
==16114== 
==16114== Use of uninitialised value of size 4
==16114==    at 0x80488A4: main (wrong3.cc:18)
Did you notice?
There should be 2 errors in this run
==16114== 
==16114== ERROR SUMMARY: 4 errors from 4 contexts (suppressed: 20 from 1)
==16114== malloc/free: in use at exit: 0 bytes in 0 blocks.
==16114== malloc/free: 1 allocs, 1 frees, 4 bytes allocated.
==16114== For counts of detected errors, rerun with: -v
==16114== No malloc'd blocks -- no leaks are possible.