北大ACM(Question-1001)

Question：http://poj.org/problem?id=1001

 1 #include <iostream>
 2 using namespace std;
 3 #define max 1000
 4 char a[max];
 5 char b[max];
 6 char c[max];
 7 int main()
 8 {
 9     memset(a,0,1000*sizeof(char));
10     memset(b,0,1000*sizeof(char));
11     memset(c,0,1000*sizeof(char));
12     char *R=(char *)malloc(6*sizeof(char));
13     int n,point;
14     while(cin>>R>>n)
15     {
16     for(int i=5,j=0;i>=0;i--,j++)
17     {
18         if(R[i]==‘.‘)
19         {
20             point=5-i;
21             j--;
22             continue;
23         }
24         a[j]=R[i];
25         b[j]=R[i];
26     }
27
28     if(n==1)
29     {
30         strcpy(c,a);
31     }
32     else
33     {
34         for(int k=1;k<n;k++)
35         {
36             int alen=strlen(a);
37             int blen=strlen(b);
38             int m,n;
39             int jw=0;
40             for(m=0;m<alen+blen;m++)
41             {
42                 int temp=0;
43                 for(n=((m-blen+1)>0?(m-blen+1):0);n<alen&&m-n<blen&&m-n>=0;n++)
44                 {
45                     temp+=(a[n]-‘0‘)*(b[m-n]-‘0‘);
46                 }
47                 temp+=jw;
48                 jw=temp/10;
49                 temp%=10;
50                 c[m]=temp+‘0‘;
51             }
52             strcpy(a,c);
53         }
54     }
55     int slen=strlen(c);
56     int q;
57     for(q=strlen(c)-1;c[q]==‘0‘&&q>=point*n;q--)
58     {
59         c[q]=0;
60     }
61     for(q=0;c[q]==‘0‘&&q<point*n;q++)
62     {
63     }
64     for(int p=strlen(c)-1;p>=q;p--)
65     {
66         if(p==point*n-1)
67         {
68             cout<<".";
69         }
70         cout<<c[p];
71     }
72     memset(a,0,1000*sizeof(char));
73     memset(b,0,1000*sizeof(char));
74     memset(c,0,1000*sizeof(char));
75     cout<<endl;
76     }
77     return 0;
78 }