Introduction

The task is to sort the array elements using bubble sort.

Program

def sort(ip_arr):
    length = len(ip_arr)
    for i in range(length - 1):
        for j in range(0, length-i-1):
            if ip_arr[j] > ip_arr[j+1]:
                ip_arr[j], ip_arr[j+1] = ip_arr[j+1], ip_arr[j]
       
ip_arr = [12, 7, 8, 21]
print("Input array is: ", ip_arr)
sort(ip_arr)
print("The sorted array is ")
for i in range(len(ip_arr)):
    print("%d" %ip_arr[i])

Output

Explanation

The first element is picked and checked against each element in the array and swapped if the elements are in wrong order.