Question

This program is to compute and write to a file the GPA for student scores read from an input file. The point values of the grades are 4 for A, 3 for B, 2 for C, 1 for D, and 0 for F. Except for the grade A, where '+' has no effect, a '+' after the letter increases the point value by 0.3, and except for F, where a '-' has no effect, a '-' after a letter decreases the point value by 0.3, so, for example, B- is worth 3 - 0.3 = 2.7 points. The weighted points for a course is the point value of the grade, multiplied by the number of units for the course. The weighted average for the GPA is then the sum of these weighted points, divided by sum of the units.
Prompt the user by "Enter name of input file: " for the name of an input file and open that file for reading. The two input files for the tests are already at the zyBooks site. They each have a list of student names with the course they have taken, of the form

Jacobs, Anthony
ECS10 4 B- ECS20 4 C+
ANS17 3 A
ANS49H 2 D
Wilson, Elaine
ECS10 4 B+
ECS20 4 C+
ANS17 3 A
ANS49H 2 D
ANS100 5 B-

with the student name on one line, and a list of that student's course names, units, and grades on a sequence of following lines, terminated by a blank line before the next student name line. The input will be terminated either by a second blank line where the next name would be, which will appear as just "\n", or by the file ending with either no new line character at the end of the last course line for the last student, or just one, which will result in just the empty string "" when reading in any more lines. (The input for the hidden second test ends with just one blank line after the last course.) To repeat this in a different way:
You need to correctly handle 3 cases:

a) The file ends at the end of the last course line, just after the last grade, with no \n character at all.
b) The input file ends with a single \n character at the end of the last grade line (as is normal on all other lines).
c) The file ends with two \n characters, one to end the last grade line, and one blank line, as would normally occur before another student name.

The program should open and write an output file named "GPA_output.txt" of the form:

Jacobs, Anthony 2.62
Wilson, Elaine 2.77

with each line containing a student name and the GPA, which must be computed by the program. The format of each line must have the name left adjusted, in a field with a total of 26 spaces, followed immediately by the GPA, with two decimal places. You can do this with a "%" style formatted output of the form:

f.write("%-26s%.2f\n" % (student_name, GPA))

or a "…".format() style formatted output of the form

f.write("{:<26s}{:.2f}\n".format(student_name, GPA))

Note that the "\n" is needed at the end of the quoted format specification, because unlike print(), f.write() does not automatically put a new line character at the end of the line.
The input given above is for the first test, and the file "GPA_input.txt" from which it was taken is in the canvas File Folder for "Week 9" of "Programs shown in class", so that you can use it for testing your program before submitting it. You will probably need to do such testing because unlike the other assignments if your program has problems that prevent it from getting to the stage of writing the output file, the error reported will just be "Could not find file: GPA_output.txt" which is not very useful. The output file for this input, "GPA_output.txt" is also in the Week 9 folder for you to compare, since white space is important here.

Answer 1

Answer:

#Take input from the user

filename=input('Enter name of input file: ')

total_units=0#Total number of units for a student

total_score=0#Total score of a student

#Assign a score to each grade. I have reduced 0.33 for each grade. Change here if you need to

grade={'A':4.0,'A-':3.67,'B+':3.34,'B':3.01,'B-':2.68,'C+':2.35,'C':2.02,'C-':1.69,'D+':1.36,'D':1.03}

try:

with open(filename,"r") as input_file:#Open the file for input(reading)

output_file=open("GPA_output.txt","w") #Create and open GPA_output.txt if it doesn't exist for writing

for student_record in input_file:#read from input file

if("," in student_record):#if there is a , that means this is the student name

student_name=student_record.strip('\n')#Remove \n from student name

continue

else:

if(" " in student_record):#If a line contains spaces then its the student's grades for a course

student=student_record.split(" ")#Split to find the coursename, units and grade

#student[0]=coursename student[1]=units student[2]=grade

total_units+=int(student[1])#Calculate total units for 1 student

total_score+=int(student[1])*grade[student[2].strip('\n')]#Find the total score of a student

#grade[student[2]] will lookup for the score that we initialized earlier

#if student has a grade as A then this will look up as grade['A'] which will return 4

#Find the total score as product of this grade and units for this course

continue

else:

if(total_units>0):#Check if score has been calculated for a student earlier

print("in")

GPA=total_score/total_units#Calculate the GPA

output_file.write("%-26s%.2f\n" % (student_name, GPA))#Write the GPA and Student Name in the required format

total_units=0#reset the units

total_score=0#reset the score

if(total_units>0):#Essential for the case when the file doesn't end with a new line(Check if total_units is not 0) which means a record is pending

#to be written to the file

GPA=total_score/total_units#Calculate the GPA

output_file.write("%-26s%.2f\n" % (student_name, GPA))#Write the GPA and Student Name in the required format

total_units=0#reset the units

total_score=0#reset the score

input_file.close()#Close the input file

output_file.close()#Close the output file

except IOError as e:

print("Problem in Opening the required file")#Print a message if file cannot be opened

Explanation:

The program has been tested for all 3 scenarios mentioned i.e.

a. If the file ends without \n

b. If the file ends with 2 \n

c. If the file ends with 1 \n

PS: The Program will run irrespective of how it ends. Even if there are many \n at the end of file, the program will be fine.