66. Detect Underflow in Unsigned Subtraction

You are given two 8-bit unsigned integers a and b. You must compute a - b, and also detect if underflow occurred (i.e., when b > a).

Return:

• The result of a - b (with wraparound if any)
• A flag carry = 1 if underflow occurred, otherwise carry = 0
   

Example-1

Input: a = 100, b = 50
Output: diff = 50, carry = 0

Example-2

Input: a = 10, b = 20
Output: diff = 246, carry = 1

Example-3

Input: a = 0, b = 0
Output: diff = 0, carry = 0