1. Running Totals CSIS 1595: Fundamentals of Programming and Problem Solving 1

2. Running Totals Goal: Creating a cumulative value based on data entered/computed by program – Generally done with a loop Algorithm: – “Accumulator” variable kept – Initialize accumulator to value before any data – Each time through loop, update accumulator based on current data in terms of: Current data Previous value of accumulator

3. Trip Mileage Example Goal: Keep track of total mileage driven on trip Algorithm: – Prompt user for mileage this stage – Increment total mileage by amount entered by user each stage – Initially: total mileage = 0 – Use sentinel loop to decide when to quit

4. Trip Mileage Example

5. Running Products Can increment running totals in ways other than addition Example: – Place a penny on first square of chess board – Double number of pennies on each subsequent square – How many pennies on each square? Design: – Initial value of pennies = 1 (number on first square) – Double pennies each time through loop by multiplying by 2 pennies *= 2 – Since we know how many squares there are, we can use a for loop from 1 to 65

6. Running Products

7. Running Maximums/Minimums May want to find largest/smallest/etc. in some list of values Example: – User enters names and corresponding grades – Program then prints name of student with highest grade

8. Running Maximums/Minimums Key idea: Each time through loop, keep track of: – Highest grade so far – Name of student with the highest grade so far Modifying accumulators in loop: – Prompt for name, grade of next student – Compare their grade with highest grade so far – If the new grade is higher: The highest grade so far is the new grade The student with the highest grade is the new name Initialization: – Prompt for name, grade of first student – Initialize highest name, grade to those values

9. Running Maximums/Minimums