Board Thread:Questions and Answers/@comment-24860891-20150424201743/@comment-5334617-20150426022303

The problem with INPUT is that things that have previously been PRINTed on the line are considered part of the user input. For instance, if you have PRINTed 40 space characters on the line that the cursor appears on, it is as if you had typed 40 space characters and then moved the cursor back to the left of the line. If you press the right button, then backspace, there are now only 39 space characters, and you can type one character, but not two: until you delete another character.

The exception is CHR$(0). If you have PRINTed CHR$(0) across the row that the cursor appears on, INPUT will behave as you expect. If you have a mixture of CHR$(0) and other characters, the behaviour is quite complex, and confusing.