Call by Reference Functions

  -- Call by Reference Functions are useful because they allow you to
     pass a reference to a variable instead of the value. This
     reference means that changing the reference argument also changes
     the variable in the calling function.

  -- We often use call by reference for input functions. For example:

   void input(int &a, int &b) {
     cout << "Please input two integers: ";
     cin >> a >> b;
     return;
   }

  This function has a void as a return type. This means the function
  can have a return statement, but that the return statement must not
  return anything.


  -- In this homework you will write a program using an input
  function, a computation function and an output function. Your main
  may look like this:

int main() {
   int  principle, rate, newPrinciple;
   input (principle,rate);
   newPrinciple = computePrinciple(principle,rate);
   output(newPrinciple,principle,rate);
}


The input function should ask the user for two integer values.  The
initial principle, the rate (as a percentage) in rate per year.

The output function will simply output the values of the 3 integers
shown, hopefully with some descriptive text describing each of the 3
pieces.


The compute function should return a new integer principle based on
the following. The new principle is equal to the old
principle plus the old principle times the rate. You need to convert
the rate to an actual decimal (and not a percentage). You can do this
by dividing by 100. You should make this computation use floating
point computation. You can do that casting to a float explicitly or by
making sure that the variables are floats.

For example the following code give the value of the rate:

rate

The following code gives teh value of the rate as a float:

(float) rate


If the input is 100 and 5, the output should be 105.
This is because 100 + 100 * 5 / 100 is 105.


If you do this computation without using floats, the result may not be
what you have intended.


To make this more interesting, you should consider adding a variable
for time. Allow the user to input an amount of time and then use a
loop to update the principle based on the amount of time that has
passed.

For example, if your rate is 5% per year and two years have gone by
the new principle would be output after two loops, the following shows
the computation:

105 = 100 + 100 * 5/100 
110.25 = 105 + 105 * 5/100