Page 397 - Computer Science V2.0 Class 11

4. Accept from the user interactively roll number and marks of students whose result needs to be updated and
update the list result.
5. Displays the result of all the students.
For this purpose, we write the following functions:
● readResult(): The function readResult() performs the following tasks:
○ Accepts from the user the number of students.
○ Accept from the user result of each student in the form of a list [rollNo, marks].
○ Constructs the list result comprising the list [rollNo, marks] for each student.
● marksUpdate(rollNo, marks): The function marksUpdate performs the following task:
○ To update the marks of a student, given his/her roll number and the updated marks. Given the roll number of
a student, the function looks for the list entry [rollNo, marks] within the list result and updates the
marks when the match is found.
● allUpdates(): The function performs all necessary updates of the results.
○ The user is asked whether more updates to the result are required. He/she is prompted to enter his/her choice
by entering y/y or N/n. If the user opts for more updates, he/she is prompted to enter roll number and revised
marks of a student, and the function marksUpdate is invoked to update the marks of a student. The process
is repeated untilthe user says, no more updates are required.
Having developed the functions marksUpdate(), readResult(), and allUpdates(), the program
merely needs to intialise the result list as an empty list and invoke these functions. (see Program 13.3)

01 def marksUpdate(rollNo, marks):
02 '''
03 objective: To update result of a student
04 Global data:
05 result: list of lists of result of all students
06 input parameters:
07 rollNo: roll number of student for updating the result
08 marks: updated marks
09 Return value: None
10 Side effect: List classResult gets updated
11 '''
12 for indx in range(len(classResult)):
13 #look for rollNo in each subslist
14 if(classResult[indx][0] == rollNo):
15 classResult[indx][1] = marks
16 break
17
18 #Input student data
19 def readResult():
20 '''
21 objective: To read result of all students
22 Global data:
23 result: list of lists of result of all students
24 Return value: None
25 Side effect: List classResult gets updated
26 '''
27 nStudents = int(input('Enter number of students: '))
28 print('Enter the list [Roll No, Marks] and press enter: ')
29 for i in range(0, nStudents):
30 #Enter student result as a list: [rollNo, marks]
31 result = eval(input('[rollNo, marks]: '))
32 classResult.append(result)
33
34 def allUpdates():

Lists and Tuples 383