C++ Comparison of String Literals

Question

I'm a c++ newbie (just oldschool c). My son asked for help with this and I'm unable to explain it. If he had asked me "how do I compare strings" I would have told him to use strcmp(), but that isn't what is confusing me. Here is what he asked:

int main() 
{ 
  cout << ("A"< "Z");
}

will print 1

int main() 
{ 
  cout << ("Z"< "A");
}

will also print 1, but

int main() 
{ 
  cout << ("Z"< "A");
  cout << ("A"< "Z");
}

will then print 10. Individually both cout statements print 1, but executed in a row I get a different answer?

Answer 1

You are comparing memory addresses. Apparently your compiler places the string literals in memory in the order it encounters them, so the first is "lesser" than the second.

Since in the first snippet it sees "A" first and "Z" second, "A" is lesser. Since it sees "Z" first in the second, "Z" is lesser. In the last snippet, it already has literals "A" and "Z" placed when the second command rolls around.