Page 238 - Computer Science Class 11 With Functions
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14 marks = int(input('Enter marks: '))
          15 sumMarks = sumMarks + marks
          16 marks = int(input('Enter marks: '))
          17 sumMarks = sumMarks + marks
          18 marks = int(input('Enter marks: '))
          19 sumMarks = sumMarks + marks
          20 marks = int(input('Enter marks: '))
          21 sumMarks = sumMarks + marks
          22 marks = int(input('Enter marks: '))
          23 sumMarks = sumMarks + marks
          24 marks = int(input('Enter marks: '))
          25 sumMarks = sumMarks + marks
          26 marks = int(input('Enter marks: '))
          27 sumMarks = sumMarks + marks
          28 averageMarks = sumMarks/nStudents
          29 print('average marks:', averageMarks)
        So far, so good. But what if we were to find the average of the marks obtained by a group of eleven students. Well, we
        will have to modify the program by including two more statements, one for accepting the marks of one more student
        from the user and another for adding the marks read to the sum (sumMarks). If we were to compute the average
        marks of a students' group of size 100, our program would run into over 200 lines of code. The situation would be even
        worse if we were to find the average of the marks obtained by 1000 students. Clearly, this way of writing a program
        won't work to solve problems that require a lot of calculations. Thanks to Python's for and while statements, a
        piece of code can be run over and over again without having to write the same code repeatedly. Repeated execution
        of a statement or a sequence of statements is called looping. Hence, for and while statements are also called for
        and while loops. The statement or a sequence of statements being executed in a loop is called the loop's body. An
        execution of the loop's body is called an iteration of the loop.
        10.2 range()

        Even though we want to know how to shorten Program 10.1 (which would get even longer if we calculated the average
        marks of a lot of students), let's first learn about the built-in function range(), which will help us when we talk about
        the for statement. The function range() returns a sequence of numbers within the specified range. The range()
        function may be invoked using any of the following formats:
        Syntax
            range(stop)
            range(start, stop)
            range(start, stop, step)
        The following syntax summarises the above three formats:
            range([start,] stop [, step])
           In the above description, the arguments start and stop is optional. The default values for start and stop are 0 and 1,
          respectively.

           When these arguments are not given, the function returns a list of integers starting at 0 and ending at the integer
          stop, but not including the integer stop. For example, range(6) returns the sequence of integers: 0, 1, 2,3, 4, 5
          (excluding 6).

           When the range() function is invoked with two arguments, range(start, stop), it returns a sequence of
          integers beginning with start and going up to stop. For example, range(2,6) returns the sequence of integers: 2,
          3, 4, 5. Similarly, range(-2, 6) returns the sequence of integers: -2, -1, 0, 1, 2, 3, 4, 5.
           When the third argument is also specified, the function call range(start, stop, step) returns a sequence
          of integers beginning with start and going up to stop, but stepping over in chunks of size step. For example, the
          function call range(-7, 20, 4) returns the sequence of integers: -7, -3, 1, 5, 9, 13, 17. Similarly, the function call
          range(30, -10, -8) returns the sequence of integers: 30, 22, 14, 6, -2.

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