002：求两个整数的最大公约数和最小公倍数

 1 #include <stdio.h>
 2 
 3 int main()
 4 {
 5     unsigned long a, b, c=0;       //两个整数和临时变量
 6     unsigned long lcm=0, gcd=0;    //最小公倍数和最大公约数
 7 
 8     while( 1 )
 9     {
10         printf("Please input two positive integers(spacebar as separator):");
11         scanf("%lu %lu", &a, &b);
12         if(a <= 0 || b <= 0)
13         {
14             printf("Input error!\n");
15             continue;
16         }
17         else
18             break;
19     }
20 
21     unsigned long ra=a ,rb=b;      //保存原始数据
22 
23     while(a % b != 0)
24     {
25         c = a % b;
26         a = b;
27         b = c;
28     }
29     gcd = b;
30     lcm = (ra * rb)/gcd;           //使用原始数据计算lcm
31     printf("Their Greatest Common Divisor is %lu.\n", gcd);
32     printf("Their Least Common Multiple is %lu.\n", lcm);
33     
34     return 0;
35 }