# Bucket sort (C)

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Bucket sort is possibly the simplest distribution sorting algorithm. The essential requirement is that the size of the array from which the elements to be sorted are drawn is a small, fixed constant, say n.

```<<sort function>>=
void bucketSort(int array[], int n) {
int i, j;
int count[n];
initialize counters
count amount of each array-number
rearrange order of array
}
```

For example, suppose that we are sorting elements drawn from {0, 1, . . ., n-1}. The integers in this set can be of the range 0 until (n-1). Bucket sort uses n counters. These counters first have to be initialized:

```<<initialize counters>>=
for(i=0; i < n; i++) {
count[i] = 0;
}
```

To we can determine the amount of each number in the array we want to sort.

```<<count amount of each array-number>>=
for(i=0; i < n; i++) {
(count[array[i]])++;
}
```

After we've determined all needed information about the array we want to sort. The array can be sorted. `j` holds the current position in the array to sort. `i` holds the current position in the counter array,

```<<rearrange order of array>>=
for(i=0,j=0; i < n; i++) {
for(; count[i]>0; (count[i])--) {
array[j++] = i;
}
}
```

## Putting it together

To check the bucket sort, we output the data:

```<<output the array>>=
for (i = 0;i < n;i++) {
printf("%d ", array[i]);
}
printf("\n");
```

Putting it all together with a example array.

```<<bucketsort.c>>=
#include <stdio.h>
sort function
int main() {
int array[] = {1,3,4,6,4,2,9,1,2,9};
int n = 10;
int i;
output the array
bucketSort(array, n);
output the array
return 0;
}
```

This generates following output:

```1 3 4 6 4 2 9 1 2 9
1 1 2 2 3 4 4 6 9 9
```