ECS Baruch Lab 12 Spring 2019 Name

Transcription

1 ECS Baruch Lab 12 Spring 2019 Name I. More input files. Download the file cookiesales.txt and the code file processcookies.py. cookiesales has information about some scouts and how many cookie orders they made for 3 kinds of cookies. processcookies.py reads the file, computes how many kids are listed, and computes total sales of Samoas. Run the program. Read it to understand how it works. A. For the line print("there are " + str(numkids) + " kids selling cookies.") why do I use str(numkids)? For the line sumsamoas=sumsamoas + int(saleslinelist[1]) why do I use int(saleslinelist[1])? In the loop I have print(inputlist[i].rstrip()) What happens differently if I use print(inputlist[i]) as in the comment above it? (You can try it.) Explain. For the line for i in range(3,numlines,2): would it work properly if I use numlines+1 instead of numlines? How many lines are in the file? How many lines would be in the file if there were 4 kids? How many lines would be in the file if there were 5 kids? How many lines would be in the file if there were k kids? B. Add code that will print the following line for Susie's sales: Susie Fong The name is left justified and the numbers are right justified, with one space after them. (Use values read from the file, don't just print(10).) Here is the line on graph paper: S u s i e F o n g Run the program. Print the program and the output to hand in. 1

2 II. Shape calculator A. Here is a program. DO NOT RUN IT. #shapecalculator.py from math import pi def rectarea(length, width): area=length * width return area def circlearea(radius): area=pi*radius*radius return area def welcome(): print("welcome to the shape calculator!") name=input("what is your name? ") return name def askdimension(dimension): value = float(input("what is the " + dimension +"? ")) return value def main(): name = welcome() print(name+", ", end="") x = askdimension("length") #enter 4 y = askdimension("width") #enter 3 print("the area of the rectangle is " + str(rectarea(x,y))) rad = askdimension("radius") #enter 10 a= circlearea(rad) print("the area of the circle is {0:0.5} sq. cm.".format(a)) Step through main by hand, without the computer. Show the memory in this table, and output (with the input) on the next page. For memory, put a slash through a value when it is replaced by a new value. (For input, use the values in the comments.) You will not be penalized for your errors. MEMORY rectarea circlearea welcome askdimensions main length radius name dimension name width area x area value y rad a 2

3 OUTPUT B. Download the program shapecalculator.py. Run the program. Circle anything that was wrong in your output, and fix it, making sure you understand. C. Write a function trianglearea that computes and returns the area of a triangle: altitude * base. What should the parameters be? Does it return a value? Add code to the bottom of main to use functions to get the altitude and base of a triangle, and compute and print the area of the triangle. D. Write a function squarearea. It should only need one parameter. In will compute the area of a square by calling the rectarea function. (A function calling another function.) What should the parameter of squarearea be? Add code to main to use the functions to get the dimension of the square and compute and print the area of the square. E. Set dimlist = [ 5, 3, 7, 2] Using the functions we have, add code to compute and print the area of a square whose side is the first value of dimlist. You will not need to call askdimension since the values are already in the program in dimlist. Add code to compute and print the area of a circle with diameter equal to the second value of dimlist. Finally add code to compute and print the area of a rectangle whose length and width are the last two values of dimlist. All printed values should be labeled. Run the program. Print your code and output for shapecalculator. 3

4 III. Exploring the order in which functions are performed. Write the following function in the shell: >>> def doit( a ): print("in doit.", a) return a*2 Call doit( 2) Call doit("abc") Try print("here: ", doit(4), doit(6)) Which is executed first - doit(4), doit(6) or print? (You should be able to tell by looking at the output) IV. Download learningif.py. Run it several times with different sets of data, so you get all possible outcomes. In the sections below, record the values you entered and all the output (including your input. Yes, write 6 lines every time!) Write memory values next to the variable names below: 4

5 Explain the meaning of the symbols: > >= = = The line print("thank you for playing fickle pickle.") Did it execute for all values of guess or only for some values of guess? (Go back and check your output if you are not sure.) V. Modify the program. You will need some new variables. Add functions to do each of the following. a) Print "You are speeding" if the speed is greater than 55. (Obtain a speed from the user.) b) Print odd or even depending on whether date (the day of the month) is divisible by 2. (Obtain a date from the user.) Hint: Compute by hand: 1%2 =, 2%2=, 3%2 =, 4%2 =, 5%2 =,6%2 =. How can you tell if a number is odd or even? 5

6 c) Print A for a course average score of 90 or above, B for a course average score of 80 or above, but below 90, and no credit for a course average score below 80. (This is how graduate school grades work.) This uses if...elif. You do not need "and". Print your updated version of learningif.py together with its output. V. Submitting your work. Make sure your name is on this lab packet. Staple processcookies.py, shapecalculator.py, and learningif.py to the Lab 12 packet. Each program should have the output included at the bottom. Turn the lab in at the file cabinet. 6