用c++写一个银行信贷系统，要求包含申请贷款、还贷、查询贷款记录、查询还贷记录功能

好的，下面是一个简单的银行信贷系统的C++代码：

#include <iostream>
#include <string>
#include <vector>
#include <ctime>
using namespace std;

class Loan {
private:
    string name;
    int amount;
    float rate;
    int term;
    time_t start_date;
    time_t end_date;
    bool approved;
    bool repaid;

public:
    Loan(string n, int a, float r, int t) {
        name = n;
        amount = a;
        rate = r;
        term = t;
        approved = false;
        repaid = false;
    }

    string get_name() {
        return name;
    }

    int get_amount() {
        return amount;
    }

    float get_rate() {
        return rate;
    }

    int get_term() {
        return term;
    }

    time_t get_start_date() {
        return start_date;
    }

    time_t get_end_date() {
        return end_date;
    }

    bool is_approved() {
        return approved;
    }

    bool is_repaid() {
        return repaid;
    }

    void approve_loan() {
        approved = true;
        start_date = time(NULL);
        end_date = start_date + term * 86400;
    }

    void repay_loan() {
        repaid = true;
    }
};

class Customer {
private:
    string name;
    string id_number;
    vector<Loan*> loans;

public:
    Customer(string n, string id) {
        name = n;
        id_number = id;
    }

    string get_name() {
        return name;
    }

    string get_id_number() {
        return id_number;
    }

    void apply_loan(int amount, float rate, int term) {
        Loan* loan = new Loan(name, amount, rate, term);
        loans.push_back(loan);
        cout << "Loan application submitted." << endl;
    }

    void repay_loan(int index) {
        if (loans[index]->is_approved() && !loans[index]->is_repaid()) {
            loans[index]->repay_loan();
            cout << "Loan repaid." << endl;
        }
        else {
            cout << "Loan not approved or already repaid." << endl;
        }
    }

    void display_loan_history() {
        for (int i = 0; i < loans.size(); i++) {
            cout << "Loan " << i << endl;
            cout << "Name: " << loans[i]->get_name() << endl;
            cout << "Amount: " << loans[i]->get_amount() << endl;
            cout << "Rate: " << loans[i]->get_rate() << endl;
            cout << "Term: " << loans[i]->get_term() << " days" << endl;
            if (loans[i]->is_approved()) {
                cout << "Loan approved." << endl;
                cout << "Start date: " << ctime(&loans[i]->get_start_date());
                cout << "End date: " << ctime(&loans[i]->get_end_date());
            }
            else {
                cout << "Loan not approved." << endl;
            }
            if (loans[i]->is_repaid()) {
                cout << "Loan repaid." << endl;
            }
            else {
                cout << "Loan not repaid." << endl;
            }
            cout << endl;
        }
    }
};

int main() {
    Customer c("John", "1234567890");

    c.apply_loan(5000, 0.05, 30);
    c.apply_loan(10000, 0.06, 60);

    c.display_loan_history();

    c.repay_loan(0);
    c.repay_loan(1);

    c.display_loan_history();

    return 0;
}

在这个程序中，我们定义了两个类：Loan（贷款）和Customer（客户）。Loan类表示一个贷款，包括贷款人姓名（name）、贷款金额（amount）、利率（rate）、期限（term）、开始日期（start_date）、结束日期（end_date）、是否批准（approved）和是否还清（repaid）等属性。Customer类表示一个客户，包括客户姓名（name）、身份证号（id_number）和贷款记录（loans）等属性，同时还有申请贷款、还贷款、查询贷款记录、查询还贷记录等方法。

在主函数中，我们创建了一个名为c的Customer对象，并测试了它的申请贷款、查询贷款记录、还贷款和查询还贷记录等功能。