Page 210 - Computer Science Class 11 Without Functions
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Fig 9.1: Sample execution of program 9.2
        To sum up the above discussion of the for statement used in program 9.2, we give below its syntax:

          01 for control_variable in sequence:
          02        body of for loop
        In the above syntax description,
        •   for is the keyword.
        •   in is a keyword (membership operator).
        •   sequence may be a list, string, tuple or dictionary.

        •   control variable is a variable that takes the values in the sequence one by one.
        •     body of the loop may constitute a single statement or several statements, that will be executed for each value of
            the control variable in the sequence. Statements in the body of the loop are indented at the level of indentation
            next to the level at which the header:
              for control_variable in sequence / values in range:
        appears. The first statement that appears at the same level as the header marks the end of the body of the for
        statement. However, a for statement may also be the last statement of a Python script. In such a case, the end of the
        Python script marks the end of the for statement.
        We can also describe the above syntax of the for statement in the form of a flowchart (see Fig 9.2):

                                                       For each item in
                                                         sequence


                                                  Last item   True
                                                  reached?


                                                      False

                                                 Statements
                                                                        Exit for loop


                                                     Fig 9.2: for loop

        9.3.1 Using String Sequences in a for Statement

        Suppose we wish to find the number of vowels in a string. For this purpose, let us write a program that accepts as input
        a string and returns the number of vowels in it.
          01 vowels = 'AEIOUaeiou'
          02 mystr = input('Enter a String: ')
          03 count = 0
          04 for char in mystr:
          05     if char in vowels:
          06         count += 1
          07 print('vowel count:',count)
        Sample Output:

         >>> Enter a String: Madras
              vowel count: 2
        9.3.2 Factorial of a Number

        Given a non-negative integer n, we wish to compute its factorial (n!). So, we write a program to compute the
        factorial (n!) of a number num (>=0). The program accepts an integer and outputs its factorial.


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