Java Program to find GCD , LCM of two numbers

Greatest common divisor (gcd)

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The greatest common divisor (gcd)( also known as the greatest common factor (gcf), or highest common factor(hcf)) of two or more non-zero integers, is the largest positive integer that divides the numbers without a remainder.
For example, the GCD of 8 and 12 is 4.


Euclid's algorithm 

Euclid's algorithm uses a division algorithm such as long division in combination with the observation that the gcd of two numbers also divides their difference.
Formally the algorithm can be described as,

  gcd(a,0) = a (1)
gcd(a,b) = gcd(b, a mod b) (2)