求两个正整数的最大公约数？

给定两个正整数，求它们的最大公约数，对于这个算法想必大家都已经知道，解决这个问题最经典的方法是采用欧几里德算法，据说这是历史上最早的算法。

          

                     

#include <stdio.h>

#include <stdlib.h>

 

#define max(a,b)   (a) > (b) ? (a) : (b)

#define min(a,b)   (a) < (b) ? (a) : (b)

    

/*

INPUT: m,n (m >0 ,n>0)

OUTPUT: -1 error, else the common divisor of m and n

*/

int G*C*D(int m,int n)

{

     int a = max(m,n);

     int b = min(m,n);

     int remainder = 1;

     if( m<=0 || n<=0 )

     {

         return -1;

     }

     while(remainder > 0)

     {

         remainder = a % b;

         a = b;

         b = remainder;

     }

     return a;

}

      

int main(int argc, char* argv[])

{

     int first,second,result;

     if(argc != 3)

     {

         fprintf(stderr,"There should be two number/n");

         exit(-1);

     }

     first = atoi(argv[1]);

     second = atoi(argv[2]);

     result = G*C*D(first,second);

     if(result != -1)

     {

         printf("The common divisor of %d and %d is %d/n",first,second,result);

     }

     else

     {

         printf("m and n should be greater than 0/n");

     }

     return 0;

}