The document describes how to swap the values of two integer variables, num1 and num2, using a third temporary variable temp. Since directly swapping the values would lose the original value of num2, a third variable temp is used to hold the value of num2 while the value of num1 is moved to num2. Then the saved value from temp can be moved into num1, completing the swap.

1. 7 9
int num1; int num2;
The problem:
Swap the numbers contained within the two
integer variables

2. 7 9
int num1; int num2;
That’s easy right?
Can’t we just swap the values; 7 get’s replaced
with 9 and vise versa?

3. 7 9
int num1; int num2;
Unfortunately…
It doesn’t quite work like that.
We can only perform one operation at a time.

4. 7
int num1; int num2;
9
So…
We can move the value from num1 to num2.
But by doing so we lose the original value from
num2 in the process.

5. 7 9
int num1; int num2;
So how do we save it?
We need to create somewhere to place the data
from num2.

6. 7 9
int num1; int num2;
int temp;
int temp; saves the day.
We can create a third variable, temp to act as a
holding area to place the data from num2.

7. 7
int num1; int num2;
9
int temp;
int temp; saves the day.
By placing the value held within num2 into temp
we can preserve it.

8. 7
int num1; int num2;
9
int temp;
So…
Now we can move the value from num1 into
num2

9. 9 7
int num1; int num2;
int temp;
And finally…
Move the contents from temp into num1

10. It might look like…