用C语言编写网上购物系统代码

<width>46</width>
<height>13</height>
</rect>
</property>
<property name="由于网上购物系统是一个比较复杂的系统，代码量比较大，这里提供一个基于text">
<string>Port:</string>
</property>
</widget>
<widget class="QLabel" name="ba控制台的简单实现代码供你参考，仅供学习交流使用：

#include <stdio.hudRateLabel">
    <property name="geometry">
     <rect>
      <x>170</x>
      <y>40</>
#include <stdlib.h>
#include <string.h>

// 商品结构体
typedef struct {
    char name[20]; // 商品名称y>
      <width>66</width>
      <height>13</height>
     </rect>
    </property>
    <property
    float price;   // 商品价格
    int stock;     // 商品库存
} Goods;

// 用户结构体
 name="text">
     <string>Baud Rate:</string>
    </property>
   </widget>
   <widget class="QLabel"typedef struct {
    char name[20]; // 用户名
    char pwd[20];  // 密码
    float balance; // name="parityLabel">
    <property name="geometry">
     <rect>
      <x>270</x>
      <y>40 账户余额
} User;

// 购物车结构体
typedef struct CartNode {
    Goods goods;              // 商品信息</y>
      <width>46</width>
      <height>13</height>
     </rect>
    </property>
    <
    int num;                  // 商品数量
    struct CartNode *next;    // 指向下一个节点的指针
} CartNode, *CartList;

// 商品信息文件
const char *GOODS_FILE = "goods.txt";

// 用户信息文件
constproperty name="text">
     <string>Parity:</string>
    </property>
   </widget>
   <widget class="QLabel char *USER_FILE = "user.txt";

// 订单信息文件
const char *ORDER_FILE = "order.txt";

// 清空输入缓" name="dataBitsLabel">
    <property name="geometry">
     <rect>
      <x>370</x>
      <y冲区
void clearInput() {
    char c;
    while ((c = getchar()) != '\n' && c != EOF);
}

>40</y>
      <width>61</width>
      <height>13</height>
     </rect>
    </property>
// 读取商品信息
void readGoods(Goods *goods, FILE *fp) {
    fscanf(fp, "%s %f %    <property name="text">
     <string>Data Bits:</string>
    </property>
   </widget>
   <widget class="Qd", goods->name, &goods->price, &goods->stock);
}

// 读取用户信息
void readUser(User *Label" name="stopBitsLabel">
    <property name="geometry">
     <rect>
      <x>470</x>
      <user, FILE *fp) {
    fscanf(fp, "%s %s %f", user->name, user->pwd, &user->y>40</y>
      <width>51</width>
      <height>13</height>
     </rect>
    </propertybalance);
}

// 写入用户信息
void writeUser(User *user, FILE *fp) {
    fprintf(fp, "%s %s %f\n", user->name, user->pwd, user->balance);
}

// 显示商品信息
void showGoods() {
    FILE>
    <property name="text">
     <string>Stop Bits:</string>
    </property>
   </widget>
   <widget class *fp = fopen(GOODS_FILE, "r");
    if (fp == NULL) {
        printf("商品信息文件不存在!\n="QLabel" name="flowControlLabel">
    <property name="geometry">
     <rect>
      <x>430</x>
");
        return;
    }
    Goods goods;
    printf("商品名称\t商品价格\t商品库存\n");
    printf("----------------------------------      <y>40</y>
      <width>71</width>
      <height>13</height>
     </rect>
   \n");
    while (!feof(fp)) {
        readGoods(&goods, fp);
        printf("%s\t\t%.2f\t\t </property>
    <property name="text">
     <string>Flow Control:</string>
    </property>
   </widget>
   <%d\n", goods.name, goods.price, goods.stock);
    }
    fclose(fp);
}

// 用户注册
void registerUser() {
    User user;
    printf("请输入用户名：");
    scanf("%s", user.name);
    FILE *fp = fopen(USER_FILE, "rwidget class="QPushButton" name="startButton">
    <property name="geometry">
     <rect>
      <x>10</x>
");
    if (fp == NULL) {
        printf("用户信息文件不存在!\n");
        return;
    }
    User tmp;
         <y>70</y>
      <width>75</width>
      <height>23</height>
     </rect>
    while (!feof(fp)) {
        readUser(&tmp, fp);
        if (strcmp(tmp.name, user.name) == 0) {
 </property>
    <property name="text">
     <string>Start</string>
    </property>
    <property name="default            printf("用户名已存在!\n");
            fclose(fp);
            return;
        }
    }
    fclose(fp);
    printf("请输入">
     <bool>true</bool>
    </property>
   </widget>
   <widget class="QPushButton" name="stopButton">
   密码：");
    scanf("%s", user.pwd);
    printf("请输入账户余额：");
    scanf("%f", &user.balance);
    fp = fopen(USER_FILE, "a");
    writeUser(&user, fp);
    fclose(fp);
    printf("注册成功 <property name="geometry">
     <rect>
      <x>90</x>
      <y>70</y>
      <width!\n");
}

// 用户登录
User *login() {
    User *user = (User *)malloc(sizeof(User));
    printf("请输入>75</width>
      <height>23</height>
     </rect>
    </property>
    <property name="text">
    用户名：");
    scanf("%s", user->name);
    printf("请输入密码：");
    scanf("%s", user->pwd);
    <string>Stop</string>
    </property>
   </widget>
   <widget class="QLineEdit" name="saveFilePathLineEdit">
 FILE *fp = fopen(USER_FILE, "r");
    if (fp == NULL) {
        printf("用户信息文件不存在!\n");
    <property name="geometry">
     <rect>
      <x>10</x>
      <y>100</y>
      <        return NULL;
    }
    User tmp;
    while (!feof(fp)) {
        readUser(&tmp, fp);
        if (strcmp(tmp.name, user->name) == 0 && strcmp(tmp.pwd, user->pwd) == 0) {
            user->balancewidth>271</width>
      <height>20</height>
     </rect>
    </property>
   </widget>
   <widget = tmp.balance;
            fclose(fp);
            return user;
        }
    }
    fclose(fp);
    free(user);
    printf("用户名或密码错误!\n");
    return NULL;
}

// 加入购物车
void addToCart(CartList *cart, Goods *goods class="QLabel" name="saveFilePathLabel">
    <property name="geometry">
     <rect>
      <x>10</x) {
    int num;
    printf("请输入购买数量：");
    scanf("%d", &num);
    if (num <= >
      <y>130</y>
      <width>71</width>
      <height>13</height>
     </rect>
0) {
        printf("购买数量不能小于等于0!\n");
        return;
    }
    if (num > goods    </property>
    <property name="text">
     <string>Received Data:</string>
    </property>
   </widget>
->stock) {
        printf("库存不足!\n");
        return;
    }
    CartList node = *cart;
    while   <widget class="QTextEdit" name="dataTextEdit">
    <property name="geometry">
     <rect>
      <x>10 (node != NULL) {
        if (strcmp(node->goods.name, goods->name) == 0) {
            node->num +=</x>
      <y>150</y>
      <width>501</width>
      <height>211</height>
     </ num;
            goods->stock -= num;
            printf("已加入购物车!\n");
            return;
        }
        noderect>
    </property>
    <property name="readOnly">
     <bool>true</bool>
    </property>
   </widget>
  = node->next;
    }
    CartNode *newNode = (CartNode *)malloc(sizeof(CartNode));
    newNode->goods = </widget>
 </widget>
 <resources/>
 <connections/>
</ui>

最后，在mainwindow.cpp文件中初始化界面和 *goods;
newNode->num = num;
newNode->next = NULL;
if (*cart == NULL) {
*cart =串口列表：

#include "mainwindow.h"
#include "ui_mainwindow.h"
#include <QSerialPortInfo>

MainWindow:: newNode;
    } else {
        node = *cart;
        while (node->next != NULL) {
            node = node->next;
MainWindow(QWidget *parent)
    : QMainWindow(parent)
    , ui(new Ui::MainWindow)
{
    ui->setupUi(this);

    m        }
        node->next = newNode;
    }
    goods->stock -= num;
    printf("已加入购物车!\n_serialThread = new SerialThread(this);
    connect(m_serialThread, &SerialThread::finished, m_serialThread, &SerialThread::");
}

// 从购物车中删除商品
void removeFromCart(CartList *cart, const char *name) {
    CartList node = *cart, prev = NULL;
    while (node != NULL) {
        if (strcmp(node->goods.name, name)deleteLater);
    connect(m_serialThread, &SerialThread::dataReceived, this, &MainWindow::onDataReceived);

    foreach ( == 0) {
            Goods *goods = &node->goods;
            goods->stock += node->num;
            if (prev ==const QSerialPortInfo &portInfo, QSerialPortInfo::availablePorts())
    {
        ui->portComboBox->addItem(portInfo.port NULL) {
                *cart = node->next;
            } else {
                prev->next = node->next;
            }
            freeName());
    }
}

MainWindow::~MainWindow()
{
    delete ui;
}

void MainWindow::on_startButton_clicked()
{
    m_serialThread(node);
            printf("已从购物车中删除!\n");
            return;
        }
        prev = node;
        node =->setPortName(ui->portComboBox->currentText());
    m_serialThread->setBaudRate(ui->baudRateComboBox->current node->next;
    }
    printf("购物车中不存在该商品!\n");
}

// 显示购物车中的商品
void showCart(CartList cart) {
    if (cart == NULL) {
        printf("购物车为空!\n");
        returnText().toInt());
    m_serialThread->setParity((QSerialPort::Parity)ui->parityComboBox->currentIndex());
    m;
    }
    printf("商品名称\t商品单价\t商品数量\t商品总价\n");
    printf("----------------------------------------------\n");
_serialThread->setDataBits((QSerialPort::DataBits)ui->dataBitsComboBox->currentIndex());
    m_serialThread->setStopBits    float totalPrice = 0;
    while (cart != NULL) {
        Goods *goods = &cart->goods;
        printf("%s((QSerialPort::StopBits)ui->stopBitsComboBox->currentIndex());
    m_serialThread->setFlowControl((QSerialPort::\t\t%.2f\t\t%d\t\t%.2f\n", goods->name, goods->price, cart->num, goods->FlowControl)ui->flowControlComboBox->currentIndex());
    m_serialThread->setSaveFilePath(ui->saveFilePathLineEdit->text());
   price * cart->num);
        totalPrice += goods->price * cart->num;
        cart = cart->next;
    }
    printf(" m_serialThread->start();
}

void MainWindow::on_stopButton_clicked()
{
    m_serialThread->stop();
}

void MainWindow::on总价：%0.2f元\n", totalPrice);
}

// 生成订单
void generateOrder(User *user, CartList cart) {
    if (cart == NULL) {
        printf("购物车为空!\n");
        return;
    }
    FILE *fp =DataReceived(const QByteArray &data)
{
    ui->dataTextEdit->insertPlainText(data);
}

这样，就完成了一个基于QT的多线程串口数据读取和保存的程序。