Change a pseudo-code such that we get rid of a loop

Question

I have the following pseudo-code:

read n
p <- 1;
m <- 0;
k <- 0;
while ( n != 0 )
    read x
    for ( i <- 1, k )
        x <- [x / 10]

    if ( x != 0 )
        c <- x % 10
    else
        c <- n % 10

    m <- c * p + m
    n <- [n / 10]
    p <- p * 10
    k <- k + 1
write m

and I have to transform this code such that we have just 1 loop. I went over examples over and over again and I don't see what I should do. I think we need that first while loop so I kept trying to get rid of that for loop function but I don't see how I could get the same behavior with just one loop.

(Excuse the terrible style of pseudo-code)

Answer 1

If you are talking about the

for ( i <- 1, k )
    x <- [x / 10]

loop, it divides x by 10 ** k, and

x <- [x / 10**k]

accomplishes exactly what the loop does. If you have a feeling that raising to a power is a loop in disguise, consider

power_of_ten = 1
while ( n != 0 )
    read x
    x <- [x / power_of_ten]
    ....
    power_of_ten <- power_of_ten * 10