PrimesBetween | Topcoder Archive

Problem Statement

A prime number is one that has exactly two divisors: 1 and itself. The first few primes are 2, 3, 5, 7, 11.

Given start and end, how many prime numbers are there between those bounds, inclusive?

Definition

Class:: PrimesBetween
Method:: count
Parameters:: int, int
Returns:: int
Method signature:: int count(int start, int end)
(be sure your method is public)

Constraints

start will be between 1 and 100, inclusive.
end will be between start and 100, inclusive.

Examples

```
2
```
```
11
```
```
Returns: 5
```
These are the primes listed in the problem statement.
```
8
```
```
10
```
```
Returns: 0
```
Note that none of 8, 9, or 10, are prime, so we return 0.
```
12
```
```
20
```
```
Returns: 3
```
The primes here are 13, 17, 19.
```
20
```
```
30
```
```
Returns: 2
```
23 and 29.

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