#include<stdio.h>
int main()
{
    int a,b,c;
    for(;scanf("%d %d",&a,&b)!=EOF;)
    {   c=a*b;
        if(a==0&&b!=0)
             printf("%d %d\n",b,a);
        else if(a!=0&&b==0)
             printf("%d %d\n",a,b);
        else
        {
            while(a!=b)
                  {if(a>b)
                    a=a-b;
                  if(a<b)
                    b=b-a;}
                printf("%d %d\n",a,c/a);
        }
    }
}

简单说说：
     if(a*b == 0)
           {printf("%d 0\n",a+b);continue;}
     c=a*b;
Loop_next:
     if(a>b) {a-=b;goto Loop_next;}
     if(b>a) {b-=a;goto Loop_next;}
     printf("%d %d\n",a,c/a);

thank you

简单说说：

就是求个最大公约数和最小公倍数，只是把while换成goto省不了多少时间。

楼主不知从哪学的更相减损术，这种算法不多见。相比而言辗转相除法应该更常见也更有效，怎么就没用呢？

演示一下：

#include <stdio.h>
int main()
{
    int a, b, c, r;
    for(; scanf("%d%d", &a, &b) != EOF; printf("%d %d\n", b, c / b))
    for(b = (c = a * b) ? b : a + b; r = a % b; a = b, b = r);
    return 0;
}