int x=126, y=105;do { if(x>y) x=x-y; else y=y-x;} while(x!=y);printf("%d",x); The output of the given C code segment is ________ . (Answer in integer)

The given code implements the Euclidean algorithm for computing the greatest common divisor (GCD) of two numbers using repeated subtraction.

Initially:

• $x = 126$, $y = 105$

Trace of the loop:

1. $x > y$ ($126 > 105$) $\implies x = 126 - 105 = 21, y = 105$

2. $x < y$ ($21 < 105$) $\implies y = 105 - 21 = 84, x = 21$

3. $x < y$ ($21 < 84$) $\implies y = 84 - 21 = 63, x = 21$

4. $x < y$ ($21 < 63$) $\implies y = 63 - 21 = 42, x = 21$

5. $x < y$ ($21 < 42$) $\implies y = 42 - 21 = 21, x = 21$

6. $x = y = 21$, loop terminates.

Then, printf("%d", x); prints 21.