Question

Python

4. while loops/String Manipulation Review (50%) The consumer price index (CPI) indicates the average price of a fixed basket of goods and services. It is customarily taken as a measure of inflation and is frequently used to adjust pensions. The CPI was 9.9 in July 1913 and 238.25 in July 2014. This means that $9.90 in July 1913 had the same purchasing power as $238.25 in July 2014 Assuming that the CPI will rise at 2.5% per year in the future, in how many years will the CPI at least double from its July 2014 level? What year will it be? Create a program named: Lab5Set4a.py that has the user enter the maximum "times" value to calculate and display 2 times, 3 times, up to and including the entered maximum times value. Use nested while loops to solve the problem; an outer loop to count the times (2-maximum Times) and an inner loop to calculate the increase in value and years. Once you figure it out, show how many years it will take to double it, triple it, quadruple it, and quintuple it, i.e. the outer loop. This is the sample run of the program Enter maximum times the 2014 prices: 5 Consumer prices will be 2 times 2014 prices in 29 years (2043) Consumer prices will be 3 times 2014 prices in 45 years (2059) Consumer prices will be 4 times 2014 prices in 57 years (2071) Consumer prices will be 5 times 2014 prices in 66 years (2080) Remember, the entered "times" value will determine the number of output lines. E.g. Another run of the program may be Enter maximum times the 2014 prices: 6 Consumer prices will be 2 times 2014 prices in 29 years (2043) Consumer prices will be 3 times 2014 prices in 45 years (2059) Consumer prices will be 4 times 2014 prices in 57 years (2071) Consumer prices will be 5 times 2014 prices in 66 years (2080) Consumer prices will be 6 times 2014 prices in 73 years (2087)

Answer 1

Required code in Python 3 is -

Code:

if __name__ == '__main__':
   # input 'max_inc_time' : integer - the maximum number of 'times'
   max_inc_time = int(input('Enter maximum number of times: '))
   # 'inc_time' : integer - variable to keep track of times the CPI have increased
   # initialized with which shows that minimum increase that is to be calculated
   inc_time = 2
   # 'cpi_val_2014' : float - to store the value of CPI in June 2014
   cpi_val_2014 = 238.25
   # 'rate' : float - to store the rate of increase of CPI in future
   rate = 0.025
   # 'yrs_count' : integer - to store te numbr of years to attain certain value of CPI i.e. years that is required as the output
   # initialized with 0 which represents that its 2014 (for this code) and no year have elapsed
   yrs_count = 0
   # 'cur_cpi_lvl' : float - to store the CPI value after 'yrs_count' number from 2014
   # initialized with 'cpi_val_2014' which shows that current year is 2014 (for this code) and no year have elapsed
   cur_cpi_val = cpi_val_2014

   # traversing the loop till 'inc_time' is less than or equal to 'max_inc_time'
   # thus outer loop count the number of 'times'
   while inc_time <= max_inc_time:
       # loop run till the current value of CPI is not 'inc_time' of June 2014 CPI value
       while cur_cpi_val < inc_time * cpi_val_2014:
           # adding the increase of 2.5% (using 'rate') in current CPI value 'cur_cpi_val'
           cur_cpi_val = cur_cpi_val + cur_cpi_val * rate
           # incrementing the years count by 1 showing that one year have passed and the CPI value have increased.
           yrs_count += 1
       # printing the required output
       print('Consumer price will be %d times 2014 prices in %d years ( %d )' %(inc_time, yrs_count, yrs_count + 2014) )
       # incrementing the number of time CPI have increased
       inc_time += 1

ScreenShot of code in editor (for better visualization of indentation) -

main 1 if # input "max inc-time. : integer - the maximu ber of times. max_inc_time int(input('Enter maximum number of times: # .inc-tine' : integer - variable to keep track of times the CPI have increased # initialized with which shows that minimum increase that is to be calculated # .cpi-val_2814. : float -to store the value of CPI in June 2e14 cpi_val 2814 238.25 # rate' : float to store the rate of increase of CPI in future 10 rate .825 "yrs-count" integer to store te numbr of years to attain certain value of CPI i.e. years that is required as the output : ized with e which represents that its 2814 (for this code) and no year have elapsed yrs_counte # .cur_cp1_1v1. : float -to store the CPI value after .yrs-count. number from 2014 # initialized with "cpi-val-2014. which shows that current year is 2014 (for this code) and no year have elapsed cur_cpǐyal , cpi-val-2014 14 16 17 s 19 2e 21 # traversing the loop till ·inetine, is less than or equal to ,max-inc-time. # thus outer loop count the number of 'times while inctime <max inc_time: # loop run till the current value of CPI is not ,inc-tine' of June 2014 CPI value while cur cpi valinc time cpival 2814: # adding the increase of 2.5% (using .rate') in current CPI value -cur-cpi val. cur cpi val cur_cpi val cur_cpi val rate # incrementing the years count by 1 showing that one year have passed and the CPI value have increased. yrs_count1 24 25 26 # printing the required output print('consumer price will be ed tines 2014 prices in Xd years (划)' %(inc-time, yrs-count, yrs count + 2814) ) # incrementing the number of time CPI have increased inc_time +1 28 29 30 31

Output:

Enter maximum number of times: 6 Consumer price will be 2 times 2014 prices in 29 years 2043) Consumer price will be 3 times 2014 prices in 45 years 2059) Consumer price will be 4 times 2014 prices in 57 years 2071) Consumer price will be 5 times 2014 prices in 66 years 2080) Consumer price will be 6 times 2014 prices in 73 years 2087)

Note:

The Python version used for the execution of code is 3.6.1. The outer loop runs one less than the maximum number of times or 'max_inc_time'. While the inner loop runs till the current value of CPI is not equal to required times (more precisely, 'inc_time') of June 2014 CPI value. 'cur_cpi_val' is increased at a rate of 2.5% per annum which is reflected in line 24.