The second sentence defines the integer array B, which contains five elements.
For begins to enter a loop statement and ends at next.
When k=0,
A(0+ 1)= 1 (the first input number is1) The val function is a function that is converted into numbers.
B(3-0)=a(0+ 1), that is, b(3)=a( 1)= 1.
When k= 1
A( 1+ 1)=3 (the number 3 entered for the second time)
B (3-1) = a (1+1), that is, b(2)=a(2)=3.
When k=2
A(2+ 1)=5 (the number 5 entered for the third time)
B(3-2)=a(2+ 1), that is, b( 1)=a(2)=5.
When k=3
End the loop. At this point, the value of k remains at 3.
Debug.print means output, b(k) means b(3), and the value of b(3) is the value when k=0, that is, 1.