CIS 111 Repetition

• Solve problems using Python repetition
• Use Python while statements
• Use Python for statements
• Use Python nested repetition
• Validate user input

• loop body: the statements within a loop
• accumulator: a variable used to sum up values
• counter controlled: a loop where the number of repetitions are controlled by a variable used as a loop counter
• loop counter: a variable used to control the number of times a loop executes, usually by counting up or down
• sentinel value: a special value in the input data used to signal the end of input or special processing
• priming read: a read of input before a loop to decide if the loop will run at all which is repeated at the end of the loop body

i = 1 while i <= 10: print(i) i = i + 1

sum = 0 strIn = input("Enter number to add (QUIT to exit): ") while strIn.upper() != "QUIT": num = float(strIn) sum = sum + num strIn = input("Enter number to add (QUIT to exit): ") else: print("The sum is %f" % sum)

valid = False while not valid: n = int(input("Enter an integer from 1 through 10: ")) if n < 1: print("Error: Below minimum value of 1"); elif n > 10: print("Error: Above maximum value of 10"); else: valid = True print("You entered: %d" % n)

for letter in "CIS 111": print(letter)

for num in [1, 7, 12, -4, 5]: print(num)

for num in 1, 7, 12, -4, 5: # parentheses optional around tuple print(num)

sum = 0 for n in range(1, 101, 2): # 1, 3, ..., 99 sum = sum + n print("The sum is %f" % sum)