The Language

Each program has access to two pieces of data:

• an array of 30000 integers, initially all set to zero
• an index into the array, called the pointer, initially set to zero

Both variables are implicit: the program never refers to them directly.

The language consists of eight commands, each of a single character:

•   >   Increment the pointer.
•   <   Decrement the pointer.
•   +   Increment the integer at the pointer.
•   -   Decrement the integer at the pointer.
•   .   Output the integer at the pointer.
•   ,   Input an integer into the slot at the pointer.
•   [   If the integer at the pointer is zero, jump forward to the matching ].
•   ]   If the integer at the pointer is not zero, jump backward to the matching [.

Any other character in a program is ignored, including spaces.

The I/O operators work with ASCII values. For example, outputting a 65 prints a capital "A".

Some Programs

This program    ,.    echoes one character from stdin back to stdout.

What do these programs do?

•    +++++++.


•    ,[.,]

How about this one?

++ > +++++
[
  < +
  > -
]
< .