Week 5: Friday
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Q1. (40)

Write a program that takes two real numbers as input from the user and an
operator from the set {+,-,*,/,^}. The operator is input as a character. Print
an error if the operator is outside the set of 5 characters. The ^ operator
implements the power function, i.e., x^y = x raised to the power of y.

The main program then should call a function cal with three parameters (the two
numbers and the operator) which would check which operation to perform and then
return the corresponding value.

Example:
If input is
5 8 -
then output is
-3

Q2. (60)

Define a function sqn for all positive integers that returns the sum of squares
of digits of n in decimal representation.  It is a mathematical fact that
starting from any arbitary positive integer n, if we keep on applying sqn, we
shall eventually get either 1 or 89.

For example
sqn(17) = 50, sqn(50) = 25, sqn(25) = 29, sqn(29) = 85, sqn(85) = 89
sqn(100) = 1

For each positive integer n, the smallest number of times we need to apply the
function sqn till we get 1 or 89 is called the depth of the function. So, in
the above cases depth for n = 17 is 5 and depth for n = 100 is 1.

Write a main program that takes as input a positive integer n from the user and
then prints the depth of sqn(n). Your program should have a main function and a
sqn function.