小数转分数

 1 #include<stdio.h>
 2 #include<string.h>
 3 #define LL long long
 4 
 5 char s[20];
 6 
 7 LL GCD(LL a, LL b)//求最大公约数 
 8 {
 9     LL c;
10     while(b)
11     {
12         c = a % b;
13         a = b;
14         b = c;
15     }
16     return a;
17 }
18 
19 int main()
20 {
21     int T;
22     scanf("%d", &T);
23     while(T --)
24     {
25         LL x = 0, y = 1;
26         int flag = 0, id;
27         scanf("%s", s);
28         int len = strlen(s);
29         for(int i = 2; i < len; i ++)
30         {
31             if(s[i] == ‘(‘)
32             {
33                 flag = 1;
34                 id = i;
35                 break;
36             }
37             x = x * 10 + (s[i] - ‘0‘);//分子扩大多少 
38             y *= 10;//分母就除去多少 
39         }
40         if(flag == 0)  //没有循环小数
41         {
42             LL temp = GCD(x, y);
43             printf("%lld/%lld\n", x / temp, y / temp);
44         }
45         else //有循环小数 利用循环小数的性质求解 
46         {
47             LL xx = x, yy = y;
48             id ++;
49             for(int i = id; i < len; i ++)
50             {
51                 if(s[i] == ‘)‘)
52                     continue;
53                 xx = xx * 10 + (s[i] - ‘0‘);
54                 yy *= 10;
55             }
56             LL a = xx - x;
57             LL b = yy - y;
58             LL temp = GCD(a, b);
59             printf("%lld/%lld\n", a / temp, b / temp);
60         }
61     }
62     return 0;
63 }