The Accumulator Pattern

One of the most useful loop patterns: start a variable at 0, then add to it every time through the loop, building up a total:

total = 0
for i in range(1, 6):
    total += i
print(total)

prints 15 (that's 1 + 2 + 3 + 4 + 5).

Your turn: read a number n. Compute and print the sum of every whole number from 1 to n (inclusive).