Sream States

​State refers to the overall configuration of information

When you change a variable's value, you change the state. This may or may not affect a future step of the computation, but it probably does(otherwise, what is the point of the variable)

What is the state of a stream?

• Good

  • Location in file

  • End of File

• Bad

  • Problems with the stream itself

    • Internet goes down

    • Printer loses power

    • Any kind of crash or break

  • Input is not what is expected (Logical)

    • expected type A, got (incompatible) type B

Robustness

• Recall that we want our programs to be robust.

  • i.e. they should not crash on unexpected input!

• Streams store state information in flags (i.e. bits)

• We can use stream state information to recover gracefully when there are problems with streams.

Stream State Flags

Stream State Functions