This exercise will show case two things:

1. Control structures
2. How to structure your program correctly

Control structures

Similar to other languages Python support various control structures such as:

1. If...else
2. For
3. While
4. Break, continue
5. But, no swtich

Making our Program DRY

DRY stands for Don't repeat yourselves

One should not repeat the same functionality or copy the same code again. So, we use functions just like the one we did in the previous exercise.

However, the way we structured the program does not work well in the context of import.

Define a new function



In [1]:

    
def print_n_stars(n):
    """
    Prints n no. of stars
    
    Arguments:
    n: number of stars to print
    """
    for i in range(n):
        print "*", # having a ',' tells print not to insert a new line after print

    print '' # inserts a new line after the loop
    return

Changing how function is called

Instead of immedialtely calling the function, we wrap the function call with an if condition:

if __name__ == '__main__':

Which is check if the script is run alone.



In [2]:

    
if __name__ == '__main__':
    m = 5
    i = 0
    while True:
        if i < m:
            i = i +1
            print_n_stars(i)
        elif i==m:
            i = i +1
            print('Elif reached')
        else:
            print('Stopping the loop')
            break









    



* 
* * 
* * * 
* * * * 
* * * * * 
Elif reached
Stopping the loop

However, this function call will not be called when imported in other scripts.