what that code do?

Question

class vec:
def __init__(self,x,y):
self.x=x
self.y=y
def __add__(self,other):
return vec(self.x+other.x,self.y+other.y)
v1=vec(3,4)
v2=vec(1,2)
r= v1+v2
print r.x*r.y

Answer 1

It does this:
# Declare the class
class vec:

# Constructor to save parameters in the instance
def __init__(self,x,y):
self.x=x
self.y=y

# Add operator to create a new instance with sum
# of x & y for the parameters
def __add__(self,other):
return vec(self.x+other.x,self.y+other.y)

# Create v1 with v1.x=3 & v1.y=4
v1=vec(3,4)

# Create v2 with v2.x=1 & v2.y=2
v2=vec(1,2)

# Add v1 & v2 creating r with r.x=4 (3+1) &
# r.y=6 (4+2)
r= v1+v2

# Print 24 (4*6)
print(r.x*r.y)