hello

how can i swap between the array

with to elements or couple of numbers for example i got

a { 5 , 2 , 3 , 7 }

b { 2 , 7 , 1 , 9 }

how can i swap between 2 and 7
7 & 3
1 & 2
3 & 7

what should i write i mean the code ?