#include <stdio.h>
#include <time.h>
#include <windows.h>

#define _MIN(x,y) (((x)>(y))?(x):(y))

int GetGcd1(int m,int n)/* 連續整數檢測法 */
{
	int t;
	t=_MIN(m,n);
	while(t>0)/* 測試t的每個值 */
	{
		if(m%t==0 && n%t==0)
			break;
		else
			t--;
	}

	return t;
}

int GetGcd2(int m,int n)/* 歐幾里得演算法 */
{
	int r;
	while((r=m%n)!=0)
	{
		m=n;
		n=r;
		r=m%n;
	}
	return n;
}

int GetGcd3(int m,int n)/* 分解質因數法 */
{
	int i,min,gcd;  

	min = _MIN(m,n); 
	gcd =1;       
	for(i=2;i<=min;i++) 
	{   
		while(m>0 && n>0 && m%i ==0 && n%i ==0)/* 找到公因式 */
		{  
			gcd*=i;
		    m/=i;
			n/=i; 
		}  
	}
	
	return gcd;
}

int main(int argc,char** argv)
{
	int m,n,gcd;
	double time;

	clock_t start,end;
	printf("enter two integers:\n");
	scanf("%d%d",&m,&n);

	start=clock();
	gcd=GetGcd1(m,n);	
	Sleep(1000);	
	end=clock();
	time=(double)(end-start)/CLOCKS_PER_SEC;
	printf("Great common divisor(GetGcd1):%d\n",gcd);
	printf("Time:%f\n",time);

	start=clock();
	gcd=GetGcd2(m,n);	
	Sleep(1000);	
	end=clock();
	time=(double)(end-start)/CLOCKS_PER_SEC;
	printf("Great common divisor(GetGcd2):%d\n",gcd);
	printf("Time:%f\n",time);

	start=clock();
	gcd=GetGcd3(m,n);	
	Sleep(1000);	
	end=clock();
	time=(double)(end-start)/CLOCKS_PER_SEC;
	printf("Great common divisor(GetGcd3):%d\n",gcd);
	printf("Time:%f\n",time);

	return 0;
}