模板：求A/B高精度值

http://lfyzit.com/problem/42

#include<iostream>
#include<cstdio>
#include<cstring>
using namespace std;
int main(){
int a, b, x[21];               
    cin>>a>>b;
    printf("%d/%d=%d.", a, b, a/b); 
    for(int i=1; i<=20; i++){      
        a%=b;
        a*=10;
        x[i]=a/b;
    }
    int i=20;
    while(x[i]==0 && i>1) i--;     
    for(int j=1; j<=i; j++)         
        printf("%d", x[j]);
    return 0;
}