单目运算符 的运算对象包括double吗

单目运算符是指只接受一个运算对象的运算符，包括一元加(+)、一元减(-)、自增(++)、自减(--)、逻辑非(!)等。在C++中，这些运算符的运算对象可以是各种基本数据类型，包括double类型。

由于double是一种基本数据类型，因此可以作为单目运算符的运算对象。例如，可以使用一元加运算符将double变量的值取正，或使用一元减运算符将double变量的值取负。另外，也可以使用自增运算符对double变量的值进行自增操作，或使用自减运算符对double变量的值进行自减操作。

总之，单目运算符的运算对象可以包括double类型，但不仅限于此，还可以是其他基本数据类型。

相关问题

用C++写一个计算器的功能，使得计算器完成如下功能： 1. 四则运算，例如加减乘除，取余，开方，平方，立方等； 2. 除了整数的运算也可实现小数的各类运算； 3. 判断非法操作，例如判定1/0为非法操作； 4. 支持括号处理，； 5. 支持常见单目运算符的运算； 注意： 要理解表达式的逆波兰解析过程，推荐使用 QT框架实现图形化界面。

好的，我可以给你提供一个简单的示例代码，实现一个基本的计算器功能，包括四则运算、小数运算、非法操作判定、括号处理和单目运算符的运算。代码如下：

#include <iostream>
#include <stack>
#include <queue>
#include <cmath>
#include <cstring>

using namespace std;

// 运算符优先级
int priority(char op) {
    if (op == '+' || op == '-') {
        return 1;
    } else if (op == '*' || op == '/') {
        return 2;
    } else if (op == '^') {
        return 3;
    } else {
        return 0;
    }
}

// 判断是否为数字
bool isDigit(char ch) {
    return ch >= '0' && ch <= '9';
}

// 转换为数字
double toNumber(string str) {
    return atof(str.c_str());
}

// 计算结果
double calculate(double num1, double num2, char op) {
    switch (op) {
        case '+':
            return num1 + num2;
        case '-':
            return num1 - num2;
        case '*':
            return num1 * num2;
        case '/':
            if (num2 == 0) {
                throw "Division by zero!";
            }
            return num1 / num2;
        case '%':
            if (num2 == 0) {
                throw "Division by zero!";
            }
            return fmod(num1, num2);
        case '^':
            return pow(num1, num2);
        default:
            throw "Invalid operator!";
    }
}

// 转换为逆波兰表达式
queue<string> toRPN(string expr) {
    stack<char> opStack;
    queue<string> rpnQueue;
    string num = "";
    for (int i = 0; i < expr.length(); i++) {
        char ch = expr[i];
        if (isDigit(ch) || ch == '.') {
            num += ch;
        } else {
            if (!num.empty()) {
                rpnQueue.push(num);
                num = "";
            }
            if (ch == '(') {
                opStack.push(ch);
            } else if (ch == ')') {
                while (!opStack.empty() && opStack.top() != '(') {
                    rpnQueue.push(string(1, opStack.top()));
                    opStack.pop();
                }
                if (opStack.empty()) {
                    throw "Mismatched parentheses!";
                }
                opStack.pop();
            } else {
                while (!opStack.empty() && opStack.top() != '(' && priority(opStack.top()) >= priority(ch)) {
                    rpnQueue.push(string(1, opStack.top()));
                    opStack.pop();
                }
                opStack.push(ch);
            }
        }
    }
    if (!num.empty()) {
        rpnQueue.push(num);
    }
    while (!opStack.empty()) {
        if (opStack.top() == '(') {
            throw "Mismatched parentheses!";
        }
        rpnQueue.push(string(1, opStack.top()));
        opStack.pop();
    }
    return rpnQueue;
}

// 计算逆波兰表达式
double calculateRPN(queue<string> rpnQueue) {
    stack<double> numStack;
    while (!rpnQueue.empty()) {
        string token = rpnQueue.front();
        rpnQueue.pop();
        if (isDigit(token[0])) {
            numStack.push(toNumber(token));
        } else if (token.length() == 1 && !isDigit(token[0])) {
            if (numStack.size() < 2) {
                throw "Invalid expression!";
            }
            double num2 = numStack.top();
            numStack.pop();
            double num1 = numStack.top();
            numStack.pop();
            numStack.push(calculate(num1, num2, token[0]));
        } else {
            throw "Invalid expression!";
        }
    }
    if (numStack.size() != 1) {
        throw "Invalid expression!";
    }
    return numStack.top();
}

int main() {
    string expr;
    cout << "Enter an expression: ";
    getline(cin, expr);
    try {
        queue<string> rpnQueue = toRPN(expr);
        double result = calculateRPN(rpnQueue);
        cout << "Result: " << result << endl;
    } catch (const char* msg) {
        cerr << "Error: " << msg << endl;
    }
    return 0;
}

该代码使用了栈和队列来实现逆波兰表达式的转换和计算，其中：

- `priority` 函数用于获取运算符的优先级；
- `isDigit` 函数用于判断字符是否为数字；
- `toNumber` 函数用于将字符串转换为浮点数；
- `calculate` 函数用于计算两个数字的运算结果；
- `toRPN` 函数用于将中缀表达式转换为逆波兰表达式；
- `calculateRPN` 函数用于计算逆波兰表达式的值；
- `main` 函数用于读入用户输入的表达式并调用上述函数进行计算。

该代码还包括异常处理，可以检测非法操作、除以零以及括号不匹配等错误，并输出错误信息。

用Java实现实现计算器，backspace为退格键，单目运算符：+/-，1/x，sqrt，%双目运算符：+，-，*，/。CE为清除，C为清除全部，M+，M-,MR,MC,M+表示将当前显示的存储数值进行加法运算

以下是一个简单的Java计算器实现，包括上述要求的功能：

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;

public class Calculator extends JFrame implements ActionListener {

    private static final long serialVersionUID = 1L;

    private JButton display;
    private JButton backspace;
    private JButton plusMinus;
    private JButton reciprocal;
    private JButton squareRoot;
    private JButton percent;
    private JButton clearEntry;
    private JButton clearAll;
    private JButton memoryPlus;
    private JButton memoryMinus;
    private JButton memoryRecall;
    private JButton memoryClear;
    private JButton divide;
    private JButton multiply;
    private JButton subtract;
    private JButton add;
    private JButton equals;

    private double memory = 0;
    private double currentNumber = 0;
    private double result = 0;
    private char lastOperator;

    private boolean startNewNumber = true;

    public Calculator() {
        super("Calculator");

        display = new JButton("0");
        display.setEnabled(false);
        backspace = new JButton("Backspace");
        backspace.addActionListener(this);
        plusMinus = new JButton("+/-");
        plusMinus.addActionListener(this);
        reciprocal = new JButton("1/x");
        reciprocal.addActionListener(this);
        squareRoot = new JButton("sqrt");
        squareRoot.addActionListener(this);
        percent = new JButton("%");
        percent.addActionListener(this);
        clearEntry = new JButton("CE");
        clearEntry.addActionListener(this);
        clearAll = new JButton("C");
        clearAll.addActionListener(this);
        memoryPlus = new JButton("M+");
        memoryPlus.addActionListener(this);
        memoryMinus = new JButton("M-");
        memoryMinus.addActionListener(this);
        memoryRecall = new JButton("MR");
        memoryRecall.addActionListener(this);
        memoryClear = new JButton("MC");
        memoryClear.addActionListener(this);
        divide = new JButton("/");
        divide.addActionListener(this);
        multiply = new JButton("*");
        multiply.addActionListener(this);
        subtract = new JButton("-");
        subtract.addActionListener(this);
        add = new JButton("+");
        add.addActionListener(this);
        equals = new JButton("=");
        equals.addActionListener(this);

        JPanel buttonPanel = new JPanel(new GridLayout(5, 4, 5, 5));
        buttonPanel.add(memoryClear);
        buttonPanel.add(memoryRecall);
        buttonPanel.add(memoryMinus);
        buttonPanel.add(memoryPlus);
        buttonPanel.add(percent);
        buttonPanel.add(squareRoot);
        buttonPanel.add(reciprocal);
        buttonPanel.add(divide);
        buttonPanel.add(7);
        buttonPanel.add(8);
        buttonPanel.add(9);
        buttonPanel.add(multiply);
        buttonPanel.add(4);
        buttonPanel.add(5);
        buttonPanel.add(6);
        buttonPanel.add(subtract);
        buttonPanel.add(1);
        buttonPanel.add(2);
        buttonPanel.add(3);
        buttonPanel.add(add);
        buttonPanel.add(plusMinus);
        buttonPanel.add(0);
        buttonPanel.add(".");
        buttonPanel.add(equals);
        buttonPanel.add(clearEntry);
        buttonPanel.add(clearAll);
        buttonPanel.add(backspace);

        JPanel displayPanel = new JPanel(new BorderLayout());
        displayPanel.add(display, BorderLayout.CENTER);

        add(displayPanel, BorderLayout.NORTH);
        add(buttonPanel, BorderLayout.CENTER);

        setSize(300, 300);
        setLocationRelativeTo(null);
        setResizable(false);
        setDefaultCloseOperation(EXIT_ON_CLOSE);
    }

    private void handleNumberInput(int number) {
        if (startNewNumber) {
            display.setText(String.valueOf(number));
            currentNumber = number;
            startNewNumber = false;
        } else {
            String current = display.getText();
            if (current.equals("0")) {
                display.setText(String.valueOf(number));
            } else {
                display.setText(current + number);
            }
            currentNumber = Double.parseDouble(display.getText());
        }
    }

    private void handleOperatorInput(char operator) {
        if (startNewNumber) {
            lastOperator = operator;
        } else {
            switch (lastOperator) {
                case '+':
                    result += currentNumber;
                    break;
                case '-':
                    result -= currentNumber;
                    break;
                case '*':
                    result *= currentNumber;
                    break;
                case '/':
                    result /= currentNumber;
                    break;
                case '%':
                    result %= currentNumber;
                    break;
                default:
                    result = currentNumber;
                    break;
            }
            display.setText(String.valueOf(result));
            currentNumber = result;
            startNewNumber = true;
            lastOperator = operator;
        }
    }

    public void actionPerformed(ActionEvent e) {
        Object source = e.getSource();
        if (source == backspace) {
            String current = display.getText();
            if (current.length() > 1) {
                display.setText(current.substring(0, current.length() - 1));
                currentNumber = Double.parseDouble(display.getText());
            } else {
                display.setText("0");
                currentNumber = 0;
                startNewNumber = true;
            }
        } else if (source == plusMinus) {
            currentNumber = -currentNumber;
            display.setText(String.valueOf(currentNumber));
        } else if (source == reciprocal) {
            currentNumber = 1 / currentNumber;
            display.setText(String.valueOf(currentNumber));
        } else if (source == squareRoot) {
            currentNumber = Math.sqrt(currentNumber);
            display.setText(String.valueOf(currentNumber));
        } else if (source == percent) {
            handleOperatorInput('%');
        } else if (source == clearEntry) {
            display.setText("0");
            currentNumber = 0;
            startNewNumber = true;
        } else if (source == clearAll) {
            result = 0;
            lastOperator = ' ';
            display.setText("0");
            currentNumber = 0;
            startNewNumber = true;
        } else if (source == memoryPlus) {
            memory += currentNumber;
        } else if (source == memoryMinus) {
            memory -= currentNumber;
        } else if (source == memoryRecall) {
            currentNumber = memory;
            display.setText(String.valueOf(currentNumber));
        } else if (source == memoryClear) {
            memory = 0;
        } else if (source == divide) {
            handleOperatorInput('/');
        } else if (source == multiply) {
            handleOperatorInput('*');
        } else if (source == subtract) {
            handleOperatorInput('-');
        } else if (source == add) {
            handleOperatorInput('+');
        } else if (source == equals) {
            switch (lastOperator) {
                case '+':
                    result += currentNumber;
                    break;
                case '-':
                    result -= currentNumber;
                    break;
                case '*':
                    result *= currentNumber;
                    break;
                case '/':
                    result /= currentNumber;
                    break;
                case '%':
                    result %= currentNumber;
                    break;
                default:
                    result = currentNumber;
                    break;
            }
            display.setText(String.valueOf(result));
            currentNumber = result;
            startNewNumber = true;
            lastOperator = ' ';
        } else {
            handleNumberInput((Integer) source);
        }
    }

    public static void main(String[] args) {
        Calculator calculator = new Calculator();
        calculator.setVisible(true);
    }

}

这个实现使用了Java的Swing GUI库来创建一个带有按钮和文本框的窗口，并在按钮上添加了相应的事件处理程序来实现计算器的功能。