mt-gox

Your mission

Write out the transaction id with its dashes taken out.

today's brief

February 2014. Mt. Gox is handling most of the world's bitcoin trades when it freezes withdrawals and starts talking about transaction malleability. Anyone could pull a transaction off the wire and rebroadcast it with the signature written differently, which gave the same payment a brand new id. Gox went looking for the id it had written down. It never found it, so it paid out again. Bankrupt by the end of the month, 850,000 coins gone. Tidy the id up before you match it.

See it in action

normalise(out, "a1-b2-c3")

Expected result

a1b2c3

Your checklist

For your own tracking. Tests grade your code.

id is a null-terminated transaction id, and out has room for every character of id plus a terminator.
Copy id into out, leaving out every dash.
Finish out with a null byte. An id made only of dashes leaves an empty string.

More examples

normalise(out, "-9f-3d")

Expected result

9f3d

Constraints

Expected files

txid.c

Allowed functions

None. Write every helper yourself.

Back to compete

Solutions

mt-gox

Your mission

Write out the transaction id with its dashes taken out.

today's brief

See it in action

normalise(out, "a1-b2-c3")

Expected result

a1b2c3

Your checklist

For your own tracking. Tests grade your code.

id is a null-terminated transaction id, and out has room for every character of id plus a terminator.
Copy id into out, leaving out every dash.
Finish out with a null byte. An id made only of dashes leaves an empty string.

More examples

normalise(out, "-9f-3d")

Expected result

9f3d

Constraints

Expected files

txid.c

Allowed functions

None. Write every helper yourself.

Back to compete

Solutions