Question

我得到“'Operation'不是一个类或命名空间”（mainwindow.cpp文件）在我使用Operation :: ADD，Operation :: SUBTRACT，Operation :: MULTIPLY或Operation :: DIVIDE的每一行中。

main.cpp中：

#include "mainwindow.h"
#include <QApplication>

int main(int argc, char *argv[])
{
    QApplication a(argc, argv);
    MainWindow w;
    w.setWindowTitle("Calculator");
    w.resize(300, 475);
    w.show();

    return a.exec();
}

operationenum.h：

#ifndef OPERATIONENUM_H
#define OPERATIONENUM_H

enum class Operation
{
    ADD,
    SUBTRACT,
    MULTIPLY,
    DIVIDE,
    MODULO
};

#endif // OPERATIONENUM_H

mainwindow.h

#ifndef MAINWINDOW_H
#define MAINWINDOW_H

#include <QMainWindow>
#include <QLabel>
#include "operationenum.h"

namespace Ui {
class MainWindow;
}


class MainWindow : public QMainWindow
{
    Q_OBJECT

public:
    explicit MainWindow(QWidget *parent = 0);
    QLabel* text;
    void cancel();
    void plusMinusClicked();
    void modulo();
    void add();
    void subtract();
    void multiply();
    void divide();
    void equals();
    void dotBtnClicked();
    void _0BtnClicked();
    void _1BtnClicked();
    void _2BtnClicked();
    void _3BtnClicked();
    void _4BtnClicked();
    void _5BtnClicked();
    void _6BtnClicked();
    void _7BtnClicked();
    void _8BtnClicked();
    void _9BtnClicked();

    long double number1;
    long double number2;
    Operation operation;
    ~MainWindow();

private:
    Ui::MainWindow *ui;
};

#endif // MAINWINDOW_H

mainwindow.cpp

#include "mainwindow.h"
#include "ui_mainwindow.h"
#include <QPushButton>
#include <string>

MainWindow::MainWindow(QWidget *parent) :
    QMainWindow(parent),
    ui(new Ui::MainWindow)
{
    text = new QLabel("42", this);
    // Operation buttons.
    QPushButton* addBtn = new QPushButton("+", this);
    QPushButton* subtractBtn = new QPushButton("-", this);
    QPushButton* multiplyBtn = new QPushButton("x", this);
    QPushButton* divideBtn = new QPushButton("÷", this);
    QPushButton* equalsBtn = new QPushButton("=", this);
    QPushButton* cancelBtn = new QPushButton("C", this);
    QPushButton* plusMinusBtn = new QPushButton("±", this);
    QPushButton* moduloBtn = new QPushButton("%", this);
    // Digit buttons.
    QPushButton* dotBtn = new QPushButton(".", this);
    QPushButton* _0Btn = new QPushButton("0", this);
    QPushButton* _1Btn = new QPushButton("1", this);
    QPushButton* _2Btn = new QPushButton("2", this);
    QPushButton* _3Btn = new QPushButton("3", this);
    QPushButton* _4Btn = new QPushButton("4", this);
    QPushButton* _5Btn = new QPushButton("5", this);
    QPushButton* _6Btn = new QPushButton("6", this);
    QPushButton* _7Btn = new QPushButton("7", this);
    QPushButton* _8Btn = new QPushButton("8", this);
    QPushButton* _9Btn = new QPushButton("9", this);

    text -> setGeometry(0, 0, 300, 100);
    cancelBtn -> setGeometry(0, 100, 75, 75);
    plusMinusBtn -> setGeometry(75, 100, 75, 75);
    moduloBtn -> setGeometry(150, 100, 75, 75);
    divideBtn -> setGeometry(225, 100, 75, 75);
    _7Btn -> setGeometry(0, 175, 75, 75);
    _8Btn -> setGeometry(75, 175, 75, 75);
    _9Btn -> setGeometry(150, 175, 75, 75);
    multiplyBtn -> setGeometry(225, 175, 75, 75);
    _4Btn -> setGeometry(0, 250, 75, 75);
    _5Btn -> setGeometry(75, 250, 75, 75);
    _6Btn -> setGeometry(150, 250, 75, 75);
    subtractBtn -> setGeometry(225, 250, 75, 75);
    _1Btn -> setGeometry(0, 325, 75, 75);
    _2Btn -> setGeometry(75, 325, 75, 75);
    _3Btn -> setGeometry(150, 325, 75, 75);
    addBtn -> setGeometry(225, 325, 75, 75);
    _0Btn -> setGeometry(0, 400, 150, 75);
    dotBtn -> setGeometry(150, 400, 75, 75);
    equalsBtn -> setGeometry(225, 400, 75, 75);

    connect(cancelBtn, &QPushButton::clicked, this, &MainWindow::cancel);
    connect(_0Btn, &QPushButton::clicked, this, &MainWindow::_0BtnClicked);
    connect(_1Btn, &QPushButton::clicked, this, &MainWindow::_1BtnClicked);
    connect(_2Btn, &QPushButton::clicked, this, &MainWindow::_2BtnClicked);
    connect(_3Btn, &QPushButton::clicked, this, &MainWindow::_3BtnClicked);
    connect(_4Btn, &QPushButton::clicked, this, &MainWindow::_4BtnClicked);
    connect(_5Btn, &QPushButton::clicked, this, &MainWindow::_5BtnClicked);
    connect(_6Btn, &QPushButton::clicked, this, &MainWindow::_6BtnClicked);
    connect(_7Btn, &QPushButton::clicked, this, &MainWindow::_7BtnClicked);
    connect(_8Btn, &QPushButton::clicked, this, &MainWindow::_8BtnClicked);
    connect(_9Btn, &QPushButton::clicked, this, &MainWindow::_9BtnClicked);
    connect(dotBtn, &QPushButton::clicked, this, &MainWindow::dotBtnClicked);
    connect(plusMinusBtn, &QPushButton::clicked, this, &MainWindow::plusMinusClicked);

    operation = Operation::ADD;
    number1 = 0;
    number2 = 0;
}

void MainWindow::cancel()
{
    text -> setText("");
}

void MainWindow::plusMinusClicked()
{
    if((text -> text().toUtf8()).at(0) != '-')
    {
        text -> setText("-" + text -> text().toUtf8());
    }
    else
    {
        text -> setText(text -> text().remove(0, 1));
    }
}

void MainWindow::add()
{
    number2 = (text -> text()).toDouble();
    if(operation == Operation::ADD)
    {
        number1 += number2;
    }
    else if(operation == Operation::SUBTRACT)
    {
        number1 -= number2;
    }
    else if(operation == Operation::MULTIPLY)
    {
        number1 *= number2;
    }
    else if(operation == Operation::DIVIDE)
    {
        number1 /= number2;
    }
    else if(operation == Operation::MODULO)
    {
        number1 %= number2;
    }
    operation = Operation::ADD;
    text -> setText("");
}

void MainWindow::subtract()
{
    number2 = (text -> text()).toDouble();
    if(operation == Operation::ADD)
    {
        number1 += number2;
    }
    else if(operation == Operation::SUBTRACT)
    {
        number1 -= number2;
    }
    else if(operation == Operation::MULTIPLY)
    {
        number1 *= number2;
    }
    else if(operation == Operation::DIVIDE)
    {
        number1 /= number2;
    }
    else if(operation == Operation::MODULO)
    {
        number1 %= number2;
    }
    operation = Operation::SUBTRACT;
    text -> setText("");
}

void MainWindow::multiply()
{
    number2 = (text -> text()).toDouble();
    if(operation == Operation::ADD)
    {
        number1 += number2;
    }
    else if(operation == Operation::SUBTRACT)
    {
        number1 -= number2;
    }
    else if(operation == Operation::MULTIPLY)
    {
        number1 *= number2;
    }
    else if(operation == Operation::DIVIDE)
    {
        number1 /= number2;
    }
    else if(operation == Operation::MODULO)
    {
        number1 %= number2;
    }
    operation = Operation::MULTIPLY;
    text -> setText("");
}

void MainWindow::divide()
{
    number2 = (text -> text()).toDouble();
    if(operation == Operation::ADD)
    {
        number1 += number2;
    }
    else if(operation == Operation::SUBTRACT)
    {
        number1 -= number2;
    }
    else if(operation == Operation::MULTIPLY)
    {
        number1 *= number2;
    }
    else if(operation == Operation::DIVIDE)
    {
        number1 /= number2;
    }
    else if(operation == Operation::MODULO)
    {
        number1 %= number2;
    }
    operation = Operation::DIVIDE;
    text -> setText("");
}

void MainWindow::modulo()
{
    number2 = (text -> text()).toDouble();
    if(operation == Operation::ADD)
    {
        number1 += number2;
    }
    else if(operation == Operation::SUBTRACT)
    {
        number1 -= number2;
    }
    else if(operation == Operation::MULTIPLY)
    {
        number1 *= number2;
    }
    else if(operation == Operation::DIVIDE)
    {
        number1 /= number2;
    }
    else if(operation == Operation::MODULO)
    {
        number1 %= number2;
    }
    operation = Operation::MODULO;
    text -> setText("");
}

void MainWindow::equals()
{
    text -> setText(number(number1));
}

void MainWindow::_0BtnClicked()
{
    text -> setText(text -> text().toUtf8() + "0");
}

void MainWindow::_1BtnClicked()
{
    text -> setText(text -> text().toUtf8() + "1");
}

void MainWindow::_2BtnClicked()
{
    text -> setText(text -> text().toUtf8() + "2");
}

void MainWindow::_3BtnClicked()
{
    text -> setText(text -> text().toUtf8() + "3");
}

void MainWindow::_4BtnClicked()
{
    text -> setText(text -> text().toUtf8() + "4");
}

void MainWindow::_5BtnClicked()
{
    text -> setText(text -> text().toUtf8() + "5");
}

void MainWindow::_6BtnClicked()
{
    text -> setText(text -> text().toUtf8() + "6");
}

void MainWindow::_7BtnClicked()
{
    text -> setText(text -> text().toUtf8() + "7");
}

void MainWindow::_8BtnClicked()
{
    text -> setText(text -> text().toUtf8() + "8");
}

void MainWindow::_9BtnClicked()
{
    text -> setText(text -> text().toUtf8() + "9");
}

void MainWindow::dotBtnClicked()
{
    text -> setText(text -> text().toUtf8() + ".");
}


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

Answer 1

如果使用高达5.4的gcc进行编译，则必须使用编译器选项-std=c++11
如果您使用的是gcc 6.1或更高版本，那么您不需要它。

使用gcc 5.4时，错误消息显示只有在使用c ++ 11选项进行编译时，范围内的枚举才可用。使用C ++ 11将Scoped枚举添加到c ++中。

<source>:2:1: warning: scoped enums only available with -std=c++11 or -std=gnu++11
 enum class Operation
 ^
<source>: In function 'int main()':
<source>:16:14: error: 'Operation' is not a class or namespace
  operation = Operation::ADD;
              ^
Compiler exited with result code 1

枚举类不是类或命名空间

1 个答案: