2. Programming Lecture #4 CS 101 Autumn 2006 Tariq Jadoon

3. In Lecture #3 Swapping Variables Conditional Code

4. Swapping the Contents of Two Variables X = 10 Y = 20 Temp = Y Y = X X Y 10 20 Temp 20 10

5. Swapping the Contents of Two Variables X = 10 Y = 20 Temp = Y Y = X X = Temp X Y 10 Temp 20

6. Debugging Using the Immediate Window as a scratchpad Placing Breakpoints Single stepping (F8) Placing Watches

7. Conditional Code VB has a number of block structures for conditional code: IF condition THEN action IF condition THEN action1 action2... END IF

8. Conditional Code (contd.) IF condition THEN action1 … ELSE action2 … END IF

9. Today Conditional Code (contd.) Loops

10. Conditional Code (contd.) IF condition1 THEN action1 … ElseIf condition2 THEN action2 … ElseIf condition3 THEN action3 … Else default action … END IF

11. Loops Repeat code –Counter Initial value Terminal Value Increment (step size)

12. Loops For c = 1 to 10 Step 2 action1 action2 … Next c Initial Value Terminal Value Increment Value Body of the loop Increment and check terminating condition