QT chart 写个柱状图

好的，你可以使用QT中的QChart和QBarSeries来创建柱状图。以下是一个简单的示例代码：

#include <QtCharts/QChartView>
#include <QtCharts/QBarSeries>
#include <QtCharts/QBarSet>
#include <QtCharts/QValueAxis>
#include <QtCharts/QCategoryAxis>
#include <QtWidgets/QApplication>

QT_CHARTS_USE_NAMESPACE

int main(int argc, char *argv[])
{
    QApplication a(argc, argv);

    // 创建柱状图
    QChart *chart = new QChart();
    chart->setTitle("柱状图示例");

    // 创建柱状图数据
    QBarSeries *series = new QBarSeries();
    QBarSet *set0 = new QBarSet("A");
    QBarSet *set1 = new QBarSet("B");
    QBarSet *set2 = new QBarSet("C");
    *set0 << 1 << 2 << 3 << 4 << 5;
    *set1 << 5 << 4 << 3 << 2 << 1;
    *set2 << 3 << 3 << 3 << 3 << 3;
    series->append(set0);
    series->append(set1);
    series->append(set2);

    // 设置柱状图轴
    QValueAxis *axisY = new QValueAxis();
    axisY->setTitleText("数量");
    axisY->setLabelFormat("%d");
    axisY->setRange(0, 6);
    QCategoryAxis *axisX = new QCategoryAxis();
    axisX->setTitleText("项目");
    axisX->append("第一项", 0);
    axisX->append("第二项", 1);
    axisX->append("第三项", 2);
    axisX->append("第四项", 3);
    axisX->append("第五项", 4);

    // 添加柱状图到图表
    chart->addSeries(series);
    chart->addAxis(axisX, Qt::AlignBottom);
    chart->addAxis(axisY, Qt::AlignLeft);

    // 显示图表
    QChartView *chartView = new QChartView(chart);
    chartView->setRenderHint(QPainter::Antialiasing);
    chartView->resize(400, 300);
    chartView->show();

    return a.exec();
}

这个示例代码会生成一个带有三个数据系列的柱状图。每个数据系列都由五个柱子组成，分别表示五个项目（第一项到第五项）。你可以根据自己的需要修改代码来生成不同的柱状图。