if statement - Continue the search inside a DO loop -

i wrote simple fortran code in order following: assume have integer numbers n1 , n2 have common divisors. example 3 , 6 both divided 3. here code

program test  integer i,n1,n2  write(*,*)' please enter 2 numbers: ' read(*,*)n1,n2  i=2,10,1   if(mod(n1,i).eq.0.and.mod(n2,i).eq.0)then      n1=n1/i      n2=n2/i   endif     n1=n1     n2=n2 enddo  write(*,*)n1,n2  pause  end       

this works fine example (3,6). however, there cases (4,8) in numbers have more 1 common divisor, in case 2 , 4. example (16,24). want compute maximum common divisor of 2 numbers , reduce them (i.e. 3,6 1 , 2), code returns first 1 (4,8 returns 2, 4 instead of 1,2). how should modified in order calculate maximum divisor?

many in advance!

you stay i, till if-statement false.

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in other words:

if number can divided i, don't go i+1, try divide i again.

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edit: think easiest way use do while-loop. calculate divisor, have multiply i.

gcd = 1 i=2,10,1   while (mod(n1,i).eq.0.and.mod(n2,i).eq.0)      n1=n1/i      n2=n2/i      gcd = gcd *   enddo enddo write(*,*) gcd