I was comparing two strings in C++ as follows:
if(s1 <= s2)
//do stuff
I had forgotten the intricacies of string comparison and quickly learned that in the following case:
s1 = "10.72";
s2 = "8.87";
The statement will evaluate to true and do whatever is inside the conditional. The comparison happens between the 8 and the 1. All ASCII representations of numbers are in increasing order from 48 (0) - 57 (9), and obviously 1 < 8.
I had thought that C++ took into account string length but that's incorrect. Would someone mind explaining why length is not taken into account from a C++ language design perspective?
Length is, in fact, taken into account, implicitly, through lexicographical comparison that is used when you invoke the less than < or less or equal to <= operators on strings.
Two ranges are compared element by element.
The first mismatching element defines which range is lexicographically less or greater than the other.
If one range is a prefix of another, the shorter range is lexicographically less than the other.
If two ranges have equivalent elements and are of the same length, then the ranges are lexicographically equal.
From http://en.cppreference.com/w/cpp/algorithm/lexicographical_compare
Hence, as an example
"10.72" < "10.721" // true
"10.72" == "10.72" // true (by string comparison as well as lexicographically equalness)
"10.7211" < "10.7212" // true
Why, you ask? This is not an intricity of C++, but of how to compare strings, where lexicographical comparison is one of the most common (and in my opinion, most logical) comparison methods.