# Finding Duplicate CSharp

## Finding Duplicate: A TDD Exercise

### The problem

Given an integer array of any size, we need to find if it contains duplicate elements or not, **without** using any built-in functions specifically for that and also by **not using any data structures other than arrays!**

### Approach using TDD

1. Start with a small and naive failing test, say for just 2 elements
2. Code just enough to pass it
3. Refactor if you can
4. Move ahead with a less naive failing test, this time with 3 elements
5. Code just enough to pass it
6. Refactor

Repeat the same until most non-trivial cases with more elements are passing. Once we have enough cases, we could also see at improving the code or doing it in more efficient ways!

### Some snippets to get you started

**Snippet 1**

```csharp
return array[0] == array[1];
```

**Snippet 2**

```csharp
return (array[0] == array[1] || array[0] == array[2]);
```

**Snippet 3**

```csharp
bool res = false;
for(int i = 0; i < array.Length; i++)
{
	for(int j=i+1; j < array.Length-1; j++)
	{
		if(array[i] == array[j])
			res = true;
	}
}
return res;
```

> Do you see any issue with above code? :O

**Exercise**: Try this out by using the partially completed solution:&#x20;

{% embed url="<https://github.com/raviramorg/Duplicates>" %}