Quiz 4

Consider the calculator program above:

1. List the names of all procedures declared in the program.

2. List the names of all variables declared in the program.

3. Circle all places where the value of any variable in the program is changed.

4. Look carefully at the when add.Click block and the when subtract.Click block. If I leave either text box blank and click Add the label at the bottom of the screen will say “Make sure to enter two numbers!”. If I leave either box blank and click Subtract a Runtime Error box pops up and says “The operation - cannot accept the arguments: *empty-string* *empty-string* Note: You will not see another error reported for 5 seconds.” Explain what is wrong with the subtract.Click block.

5. If I changed or to and in the add.Click block what would happen if I left only one text box blank and clicked Add?

6. Explain the difference between a global variable and a local variable.

7. Consider the following program. After I have chosen “Engle” from the ListPicker1 what text will appear in Label1? (This may be a trick question!)