This post is about a solution for the exercise 1-28 from the book The Algorithm Design Manual.

[1-28] Write a function to perform integer division without using either the / or * operators. Find a fast way to do it.
Skiena, The Algorithm Design Manual

## My solution

The exercise asks to write a method (or function) to perform a division operation without the use of classical programming language operators / and *. Let's start simply by write the method prototype that has two integer parameters, let's say $a, b \in Z$, and returns an integer $c \in Z$.

int divide(int a, int b)

To get the solution figure out the division meaning. Do you remember the cake and its slices? The statement $c = a / b$ means how many slice of size $b$ you can fit in $a$. So, just start to remove a slice of size $b$, then remove another slice of size $b$ and so on. I just count the number of whole slices that I eat :-). Therefore, the algorithm just use the subtract operetor. So, this is my solution:

public int divide(int a, int b) { int count = 0; while ( a &gt; 0 ) { a = a - b; count++; } return count; }

### Correctness

So, I've the solution but its not the end. I must be sure that it works for every integer number :-D. So, my idea is to create a table with the input ranges and expected output.
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