If N is given and I need to make a choice for a1, then using if else statements how should I apply the following condition:

(a1,N) = 1, if 2 does not divide N or 4 divides N

Answer 1

[Walter Roberson]

hint: mod(N,2)

[Neha W]

Sir, Is this the right way I am defining? I need to define 2 conditions for one statement:

if mod(N,2)~= 0
   gcd(a1,N) = 1;
elseif mod(N,4) ==0
  gcd(a1,N) = 1;
  end
end

[Walter Roberson]

That looks like it would work, if you are looping over a1 and N.

That code will not work if a1 or N are vectors.

Note that the definition you gave would also be satisfied by setting all locations to 1, since the definition does not say what should happen at any location where N has any other value.

By the way: how is that definition "making a decision about a1" ? The definition ignores a1.

[Neha W]

Thank you Sir. Actually a1 and N are integers. N is an user input and a1 is fixed.