How to find GCD of two number in c

# A Program of finding GCD of Two Number.

1. #include<stdio.h>
2. intd,x,y;
3. void s(inta,int b){
4. int z;
5. if(b>a){
6. z=a;a=b;b=z;}
7. if(b==0)
8. {d=a;
9. x=1;
10. y=0;
11. return ;}
12. s(b,a%b);
13. d=d;
14. z=x-(a/b)*y;
15. x=y;
16. y=z;}
17. int main ()
18. {inta,b;
19. scanf ("%d  %d",&a,&b);
20. s(a,b);
21. printf("\ngcd=%d   x=%d   y=%d\n",d,x,y);
22. return 0;
23. }