java 语言写上述问题
时间: 2024-10-09 09:05:24 浏览: 11
在Java中,我们可以按照类似的方式解决这个问题,这里是一个简化版的示例。首先,我们需要创建两个类,一个用于生成表达式并写入文件,另一个用于读取并计算表达式。假设我们有一个`ExpressionGenerator`类和一个`ExpressionSolver`类。
**1. ExpressionGenerator.java**
```java
import java.io.FileWriter;
import java.io.IOException;
public class ExpressionGenerator {
public static void main(String[] args) {
Scanner scanner = new Scanner(System.in);
System.out.print("请输入题目数量:");
int numQuestions = scanner.nextInt();
try (FileWriter writer = new FileWriter("question.txt")) {
for (int i = 0; i < numQuestions; i++) {
String operator = getRandomOperator();
double a = getRandomNumber();
double b = getRandomNumber();
// 自定义doubleMe函数,这里只是一个简单示例
double c = doubleMe(a);
writer.write(String.format("%s(%f,%f)%s%f%n", operator, a, b, c > 10 ? "max" : "", c));
}
} catch (IOException e) {
System.err.println("Error writing to file: " + e.getMessage());
}
System.out.println("运算表达式已写入question.txt");
}
private static String getRandomOperator() {
String[] operators = {"+", "-", "doubleMe(", ")"};
return operators[new Random().nextInt(operators.length)];
}
private static double getRandomNumber() {
return Math.random() * 10;
}
private static double doubleMe(double a) {
return a * 2;
}
}
```
**2. ExpressionSolver.java**
```java
import java.io.BufferedReader;
import java.io.FileReader;
import java.io.IOException;
public class ExpressionSolver {
public static void main(String[] args) {
try (BufferedReader reader = new BufferedReader(new FileReader("question.txt"))) {
BufferedWriter writer = new BufferedWriter(new FileWriter("answer.txt"));
String line;
while ((line = reader.readLine()) != null) {
String[] parts = line.split(" ");
String operation = parts[1];
double a = Double.parseDouble(parts[2]);
double b = operation.equals("doubleMe") ? doubleMe(Double.parseDouble(parts[3])) : Double.parseDouble(parts[4]);
switch (operation) {
case "+":
writer.write(line + "= " + (a + b) + "\n");
break;
case "-":
writer.write(line + "= " + (a - b) + "\n");
break;
case "max":
writer.write(line + "= " + Math.max(a, b) + "\n");
break;
default:
throw new IllegalArgumentException("Invalid operation: " + operation);
}
}
} catch (IOException e) {
System.err.println("Error reading or writing files: " + e.getMessage());
}
System.out.println("运算结果已写入answer.txt");
}
private static double doubleMe(double a) {
return a * 2;
}
}
```
**相关问题**:
1. Java代码中如果用户输入了非数字字符会怎样?
2. 如何改进代码使其更健壮,处理文件I/O错误和其他异常情况?
3. 你能提供一个更复杂的版本,其中doubleMe可以接受任意整数作为参数吗?