1/8+3/8

1/4-1/2

1/3-1/3

1/2

-1/4

0

代码1：

#include<stdio.h>
int main(void)
{
	int x,y,x1,y1;
	char o;
	while(scanf("%d/%d%c%d/%d",&x,&y,&o,&x1,&y1)!=EOF)
	{
		int x2,y2;
		y2=y*y1;
		if(o==‘+‘)
		  x2=x*y1+x1*y;
		else
		  x2=x*y1-x1*y;
		int max=x2>y2?x2:y2;
		for(int i=2;i<=max/2;i++)
		{
			if(x2%i==0&&y2%i==0)
			{
				x2=x2/i;
				y2=y2/i;
				i=2;
			}
		}
		if(x2==0)
		  printf("%d\n",x2);
		else if(x2%y2==0)
		   printf("%d\n",x2/y2);
		else
		   printf("%d/%d\n",x2,y2);
	}
	return 0;
}

#include<stdio.h>
int main(void)
{
	char ch[7];
	int a,b,c,d,m,n,s,t,r;
	while(scanf("%s",ch)!=EOF)
	{
		b=ch[2]-‘0‘;
		d=ch[6]-‘0‘;
		if(b!=d)
		{
			if(b>d)
			{
				t=b;
				b=d;
				d=t;
			}
			m=b;
			while(m%d!=0)
			   m=m+b;
		}
		else
		    m=b;
		a=m*(ch[0]-‘0‘)/(ch[2]-‘0‘);
		c=m*(ch[4]-‘0‘)/(ch[6]-‘0‘);
		if(ch[3]==‘+‘)
		  n=a+c;
		if(ch[3]==‘-‘)
		  n=a-c;
		t=m;
		if(n<0)
		  s=-n;
		else
		  s=n;
		printf("%d  %d  %d   %d   \n",m,s,a,c);
		while(s!=0)
		{
			r=t%s;
			t=s;
			s=r;
		}
		if((m/t)==1)
		   printf("%d\n",n/t);
		else
		   printf("%d/%d\n",n/t,m/t);
	}
	return 0;
 }