void bubbleSort(list<int> arr) {
   int i;
   int j;
   int tmp;
   for (i = 0; i < #arr-1; i++) {
       for (j = 0; j < #arr-i-1; j++) {
           if (arr[j] > arr[j+1]) {
              tmp = arr[j];
              arr[j] = arr[j+1];
              arr[j+1] = tmp;
           }
       }
    }
}

int main() {
    list<int> a;
    int i;
    a = [10, 2, 15, 8, 20, 13, 9];
    bubbleSort(a);
    for(i = 0; i < #a; ++i) {
        printi(a[i]);
    }
    return 0;
}

output:
2
8
9
13
10
15
13
20