Count trailing truths

Question

Inspired by, and in memory of, my dear friend and colleague,

Dan Baronet, 1956 – 2016. R.I.P.

He found the shortest possible APL solution to this task:

Task

Given a Boolean list, count the number of trailing truth values.

Example cases

{} → 0

{0} → 0

{1} → 1

{0, 1, 1, 0, 0} → 0

{1, 1, 1, 0, 1} → 1

{1, 1, 0, 1, 1} → 2

{0, 0, 1, 1, 1} → 3

{1, 1, 1, 1, 1, 1} → 6

Answer 1

MBASIC, 112 bytes

1 INPUT B$:T=0:FOR I=LEN(B$) TO 1 STEP -1:C$=MID$(B$,I,1):IF C$="0" THEN 4
2 IF C$="1" THEN T=T+1
3 NEXT
4 PRINT T

Just wanted to see if I could do it.

Explanation

Input is a string of 1's and 0's. String is traversed from right to left. If the current digit is a 0, bail out and print the total. If the digit is a 1, increment the total and continue to loop.

Output

? 01100
 0

? 11011
 2

? 11101
 1

? 111111
 6

Answer 2

05AB1E, 3 bytes

γθO

Try it online!

γθO  # full program
  O  # sum of...
 θ   # last...
γ    # group of consecutive equal elements in...
     # implicit input
     # implicit output