题目：

#include <iostream>
#include <iomanip>
using namespace std;

int main()
{
    unsigned int account;
    double beginning_balance, total_charges, total_credits, credit_limit;
    cout << "Enter account numbeu(or -1 to qiut):";
    cin >> account; // 输入账户
    while (account != -1)
    {
        cout << "Enter beginning balance:";
        cin >> beginning_balance; // 月初欠款
        cout << "Enter total charges:";
        cin >> total_charges; // 输入本月购买的所有商品的总金额
        cout << "Enter total credits:";
        cin >> total_credits; // 本月顾客账户存入的总金额
        cout << "Enter credit limit:";
        cin >> credit_limit; // 允许的信用额度
        double newBalance;
        newBalance = beginning_balance + total_charges - total_credits;
        cout<<setprecision(2)<<fixed;
        cout<<"New balance is "<<newBalance<<endl;
        cout<<"Account:\t"<<account<<"\nCredit limit:\t"<<credit_limit
		<<"\nBalance:\t"<<newBalance<<endl;
        if (newBalance > credit_limit)
        {
            cout << "Credit Limit Exceeded." << endl;
        }
        else
        {
            cout << endl;
        }
        cout<<"\n";
        cout << "Enter account numbeu(or -1 to qiut):";
    	cin >> account; // 输入账户
    }
    return 0;
}