PDSOJ 1048 Fibonacci Numbers(大数)

A Fibonacci sequence is calculated by adding the previous two members of the sequence,with
the first two members being both 1.
f (1) = 1,f (2) = 1,f (n > 2) = f (n ? 1) + f (n ? 2)
Your task is to take a number as input,and print that fibonacci number.

100

354224848179261915075

No generated fibonacci number in excess of 1000 digits will be in the test data,i.e. f (20) = 6765

和大数加法类似，还要注意数据的变换s1,s2,sum之间的变换，sum=s1+s2.然后字符处理

#include<iostream>
#include<cstring>
using namespace std;
char sum[1200];
int s=0,m=0,n;
int main()
{
    cin>>n;
    string s1,s2;
    int a[10000],b[10000];
    int he,i;
    s1="1";
    s2="1";
    for(m=2;m<n;m++)
    {
        memset(a,sizeof(a));
        memset(b,sizeof(b));
        a[0]=s1.length();
        for(i=1;i<=a[0];i++)
        {
            a[i]=s1[a[0]-i]-'0';
        }
          b[0]=s2.length();
        for(i=1;i<=b[0];i++)
        {
            b[i]=s2[b[0]-i]-'0';
        }
        he=(a[0]>b[0]?a[0]:b[0]);
        for(i=1;i<=he;i++)
        {
            a[i]=a[i]+b[i];
            a[i+1]=a[i+1]+a[i]/10;
            a[i]=a[i]%10;
        }
        he++;
        while((a[he]==0)&&(he>1))
        he--;
        for(i=he,s=0;i>=1;i--,s++)
        {
            sum[s]=a[i]+'0';
        }
        s1=s2;
        s2=sum;
   }
        cout<<s2<<endl;

}