PPA-4

Question

Accept a point in 2D space as input and find the region in space that this point belongs to. A point could belong to one of the four quadrants, or it could be on one of the two axes, or it could be the origin. The input is given in 2 lines: the first line is the x-coordinate of the point while the second line is its y-coordinate. The possible outputs are first, second, third, fourth, x-axis, y-axis, and origin. Any other output will not be accepted. Note that all outputs should be in lower case.

Hint

For a point (x, y), you have to construct a table such as this:

Condition	Result
Both x and y are positive	first
x is positive and y is negative	fourth

Your task is twofold. First, complete this table. How many rows does it have? Secondly, convert the conditions into Python expressions. Now, you just have to write a sequence of conditional statements and print the appropriate string. Study the following snippets:

Snippet-1

if x > 0:
    if y > 0:
        print('first')

Snippet-2

if x > 0 and y > 0:
    print('first')

Snippet-3

if x > 0 or y > 0:
    print('first')

Here is a follow-up question to help you with the second task:

• Among the three snippets, which one would you choose to include in your solution to the problem?
• What are the differences and similarities between snippet-1 and snippet-2?

Solutions

An image of the coordinate plane with the regions marked on it:

Solution-1

x = float(input())
y = float(input())

if x > 0:
    if y > 0:
        print('first')
    elif y < 0:
        print('fourth')
    else:
        print('x-axis')
elif x < 0:
    if y > 0:
        print('second')
    elif y < 0:
        print('third')
    else:
        print('x-axis')
else:
    if y != 0:
        print('y-axis')
    else:
        print('origin')

Solution-2

x = float(input())
y = float(input())

if x > 0 and y > 0:
    print('first')
elif x < 0 and y > 0:
    print('second')
elif x < 0 and y < 0:
    print('third')
elif x > 0 and y < 0:
    print('fourth')
elif x != 0 and y == 0:
    print('x-axis')
elif x == 0 and y != 0:
    print('y-axis')
elif x == 0 and y == 0:
    print('origin')

Video Solution