how can I exchange main diagonal with secondary diagonal with 2D array

Question

answer please tomorrow my exam

Answer 1

you mean to ask that to change the dimension of the data in that 2D arry
for example, consider an array of arr[2][2];
so a value 4 is in arr[0][0] then if your question is to make arr[2][2] as 4 and the value in arr[2][2] as arr[0][0] then you need to use a temporary say swapping of values

if this is the question this is a way to solve it