比較兩個分數大小

#include <stdio.h>
#include <stdlib.h>
main()
{
int i,j,k,a,b,c,d,n,x,y,tag1,tag2;
long m;
scanf("%d/%d,%d/%d",&a,&b,&c,&d);
//printf("%d%d%d%d\n",a,b,c,d);
tag1=b;tag2=d;
if(b<d){k=b;b=d;d=k;}
while(d!=0)
{
i=b%d;
b=d;
d=i;
}
m=tag1*tag2/b;
//printf("%d",m);
x=a*m/tag1;//printf("%d",x);
y=c*m/tag2;//printf("%d",y);
if(x>y)printf("yes");
if(x<=y)printf("no");
}