6.3 Accumulators and Counters

Notes

An accumulator is a variable that builds up a result as a loop runs. A counter counts how many times something happens.

total = 0
for i in range(1, 5):
total = total + i
print(total)

• total starts at 0 and gets 1, 2, 3, 4 added: 0+1+2+3+4 = 10. The program prints 10.
• Start the accumulator before the loop (0 for sums, 1 for products, "" for strings).
• Counter example: count += 1 is shorthand for count = count + 1.