以下是一个简单的Java计算器代码示例,可以进行加、减、乘、除运算:
import java.util.Scanner;
public class Calculator {
public static void main(String[] args) {
Scanner input = new Scanner(System.in);
System.out.print("请输入第一个数字:");
double num1 = input.nextDouble();
System.out.print("请输入运算符(+、-、*、/):");
char operator = input.next().charAt(0);
System.out.print("请输入第二个数字:");
double num2 = input.nextDouble();
double result;
switch (operator) {
case '+':
result = num1 + num2;
break;
case '-':
result = num1 - num2;
break;
case '*':
result = num1 * num2;
break;
case '/':
if (num2 != 0) {
result = num1 / num2;
} else {
System.out.println("错误:除数不能为0");
return;
}
break;
default:
System.out.println("错误:无效的操作符");
return;
}
System.out.println(num1 + " " + operator + " " + num2 + " = " + result);
}
}
这个计算器程序首先通过 Scanner
类获取用户输入的两个数字和一个运算符,然后根据运算符进行相应的计算,并输出结果。如果运算符无效或除数为0,程序会输出相应的错误信息。
以下是一个更复杂的Java计算器代码示例,可以进行加、减、乘、除、求幂和求平方根运算:
import java.util.Scanner;
public class AdvancedCalculator {
public static void main(String[] args) {
Scanner input = new Scanner(System.in);
System.out.print("请输入第一个数字:");
double num1 = input.nextDouble();
System.out.print("请输入运算符(+、-、*、/、^、sqrt):");
String operator = input.next();
System.out.print("请输入第二个数字:");
double num2 = input.nextDouble();
double result;
switch (operator) {
case "+":
result = num1 + num2;
break;
case "-":
result = num1 - num2;
break;
case "*":
result = num1 * num2;
break;
case "/":
if (num2 != 0) {
result = num1 / num2;
} else {
System.out.println("错误:除数不能为0");
return;
}
break;
case "^":
result = Math.pow(num1, num2);
break;
case "sqrt":
result = Math.sqrt(num1);
break;
default:
System.out.println("错误:无效的操作符");
return;
}
System.out.println(num1 + " " + operator + " " + num2 + " = " + result);
}
}
这个计算器程序除了基本的加、减、乘、除运算外,还增加了求幂和求平方根运算。如果用户输入的操作符无效,程序会输出相应的错误信息。
以下是另一个Java计算器代码示例,使用Java Swing库创建图形用户界面:
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
public class CalculatorGUI extends JFrame implements ActionListener {
private JTextField displayField;
private double num1, num2, result;
private char operator;
public CalculatorGUI() {
super("Calculator");
displayField = new JTextField();
displayField.setEditable(false);
JPanel panel = new JPanel();
panel.setLayout(new GridLayout(4, 4));
JButton[] buttons = new JButton[16];
for (int i = 0; i < 16; i++) {
buttons[i] = new JButton();
buttons[i].addActionListener(this);
panel.add(buttons[i]);
}
getContentPane().add(panel, BorderLayout.CENTER);
getContentPane().add(displayField, BorderLayout.NORTH);
setSize(300, 200);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setVisible(true);
}
public void actionPerformed(ActionEvent e) {
String input = e.getActionCommand();
if (input.equals("1")) {
displayField.setText("1");
num1 = 1;
} else if (input.equals("2")) {
displayField.setText("2");
num1 = 2;
} else if (input.equals("3")) {
displayField.setText("3");
num1 = 3;
} else if (input.equals("4")) {
displayField.setText("4");
num1 = 4;
} else if (input.equals("5")) {
displayField.setText("5");
num1 = 5;
} else if (input.equals("6")) {
displayField.setText("6");
num1 = 6;
} else if (input.equals("7")) {
displayField.setText("7");
num1 = 7;
} else if (input.equals("8")) {
displayField.setText("8");
num1 = 8;
} else if (input.equals("9")) {
displayField.setText("9");
num1 = 9;
} else if (input.equals("+")) {
displayField.setText("");
operator = '+';
} else if (input.equals("-")) {
displayField.setText("");
operator = '-';
} else if (input.equals("*")) {
displayField.setText("");
operator = '*';
} else if (input.equals("/")) {
displayField.setText("");
operator = '/';
} else if (input.equals("=")) {
num2 = Double.parseDouble(displayField.getText());
switch (operator) {
case '+':
result = num1 + num2;
break;
case '-':
result = num1 - num2;
break;