Introduction to Programming/Answers to the exercises

Checking An Error Condition

In programming there is rarely one right answer, but for something this simple, your answer should look something like this:

```    if (divisor != 0)
{
quotient = dividend / divisor;
}
else
{
ReportErrorMessage;
}
```

Fibonacci Numbers

```int fN = 0;
int fNplus1 = 1;
int counter = 0;

while (counter < 11)
{
fNplus2 = fN + fNplus1;
print fN;

fN = fNplus1;
fNplus1 = fNplus2;
counter += 1;
}
```

A variation, in Perl:

```my \$counter = 0;
my \$F = 1;
my \$prev_F = 0;

while( \$counter < 10 ) {
print \$F . "\n";

my \$x = \$F;
\$F = \$prev_F + \$F;
\$prev_F = \$x;

\$counter++;
}
```

Python 3 version :

```f = 1
prevF = 0
counter = 0

while counter < 10:     #While loop. What's underneath it runs until counter becomes (counter < 10).

counter += 1 	#You can write this line also as "counter = counter + 1". It assigns 'counter' variable to itself increased by one.
print(prevF)

prevF += f

counter += 1	#We add one to 'counter' variable before each character is printed on screen.
print(f)

f += prevF

```