Using the less than comparison operator for strings

The less-than operator on strings does a lexicographical comparison on the strings. This compares strings in the same way that they would be listed in dictionary order, generalized to work for strings with non-letter characters.

For example:

"a" < "b"
"a" < "ab"
"A" < "a"             (Since A has ASCII value 65; a has a higher ASCII value)
"cat" < "caterpillar"

For more information, look at the std::lexicographical_compare algorithm, which the less-than operator usually invokes.

As for -= and *=, neither of these operators are defined on strings. The only "arithmetic" operators defined are + and +=, which perform string concatenation.

Hope this helps!

The comparison operators implement lexicographic ordering of strings.

-= and *= are not defined for strings.