Can you explain the following circumstances in python3?

Question

why does typecasting of string into integer work in the following code
x=int(input("enter no.")
while it doesn't work in this one:
print(int("4.5"))

Answer 1

If your input is 4.5 (is a float) you will get the same error on the input line.

Answer 2

4.5 is real value so you have to use float here.

print(float("4.5"))