Are digits represented in sequence in all text encodings?

Question

This question is language agnostic but is inspired by these c/c++ questions.

How to convert a single char into an int

Char to int conversion in C

Is

Answer 1

According to K&R ANSI C it is.

Excerpt:

..."This particular program relies on the properties of the character representation of the digits. For example, the test

if (c >= '0' && c <= '9') ...

determines whether the character in c is a digit. If it is, the numeric value of that digit is

c - '0'

This works only if '0', '1', ..., '9' have consecutive increasing values. Fortunately, this is true for all character sets...."