There are also four comparison keys (e.g. [x=0]). These are only entered into a program (they have effect only when a program is running). If the indicated relation is true, the program continues with the next step. If false, the next step is skipped. Clicking on the [Inv] key and then on a decision key provides for the opposite decision. So if the [x=0] key is entered as an inverse, the test will be x<>0. Likewise the inverse of x<0 is x>=0, and so on
While you are in the program page, you can save the program to a disk file. When you click in the "Save Program" button, it shows a dialog box with the first line of the program suggested as the file name. You can accept that or enter a different name. When you click in "OK", the program will be saved. You can also load a program using the "Load Program" button, or clear the program with "Clear Program".