5、按要求编写Java程序: (1)编写一个接口:InterfaceA,只含有一个方法int method(int n); (2)编写一个类:ClassA来实现接口InterfaceA,实现int method(int n)接口方法时,要求计算1到n的和; (3)编写另一个类:ClassB来实现接口InterfaceA,实现int method(int n)接口方法时,要求计算n的阶乘(n!); (4)编写测试类E,在测试类E的main方法中使用接口回调的形式来测试实现。
时间: 2024-02-06 20:04:29 浏览: 22
InterfaceA.java:
```java
public interface InterfaceA {
int method(int n);
}
```
ClassA.java:
```java
public class ClassA implements InterfaceA {
@Override
public int method(int n) {
int sum = 0;
for (int i = 1; i <= n; i++) {
sum += i;
}
return sum;
}
}
```
ClassB.java:
```java
public class ClassB implements InterfaceA {
@Override
public int method(int n) {
int fact = 1;
for (int i = 1; i <= n; i++) {
fact *= i;
}
return fact;
}
}
```
E.java:
```java
public class E {
public static void main(String[] args) {
InterfaceA a = new ClassA();
int sum = a.method(10);
System.out.println("Sum of 1 to 10: " + sum);
InterfaceA b = new ClassB();
int fact = b.method(5);
System.out.println("Factorial of 5: " + fact);
}
}
```
输出结果:
```
Sum of 1 to 10: 55
Factorial of 5: 120
```