UVa 202 - Repeating Decimals

#include <iostream>
#include <cstring>
using namespace std;
int a,b;
int flag[30000];//记录该被除数出现的位置
int ans[10000],num,cnt;
void fuc()
{
memset(flag,0,sizeof(flag)); num=0;
while(a>0)
{
if(flag[a]>0) break;
flag[a]=num;
ans[num]=a/b;
a%=b;
a*=10; num++;
}
}
int main()
{
while(cin>>a>>b)
{
printf("%d/%d = ",a,b);
fuc();
printf("%d.",ans[0]);//整数位

if(a>0)
{
for(int i=1;i<flag[a];i++) cout<<ans[i]; //循环体前
cout<<'(';
for(int i=flag[a];i<num&&i<=50;i++)
{
cout<<ans[i];
}
if(num-flag[a]>=50) cout<<"...";
cout<<')'<<endl;
printf("   %d = number of digits in repeating cycle\n\n",num-flag[a]);
}
else
{
for(int i=1;i<num;i++)    cout<<ans[i];
cout<<"(0)\n";
printf("   1 = number of digits in repeating cycle\n\n");
}

}
}