以下是引用片段：
package org.
public class Stack ...{
public static class Link ...{
protected Object data.
protected Link next.
public Link(Object data, Link next) ...{
this.data = data.
this.next = next.
}
}
private Link head = null.
public void push(Object data) ...{
head = new Link(data, head).
}
public Object peek() ...{
return head.data.
}
public Object pop() ...{
if (head == null)
return null.
Object o = head.data.
head = head.next.
return o.
}
} 测试代码StackTest.java
package org.
import junit.framework.TestCase.
public class StackTest extends TestCase ...{
public void test1() ...{
Stack s = new Stack().
assertEquals(null, s.pop()).
s.push("a").
s.push("b").
assertEquals("b", s.peek()).
assertEquals("b", s.pop()).
assertEquals("a", s.pop()).
assertEquals(null, s.pop()).
}
public void test2() ...{
Stack s = new Stack().
assertEquals(null, s.pop()).
s.push(new Integer(1)).
s.push(new Integer(2)).
assertEquals(2, ((Integer)s.peek()).intValue()).
assertEquals(2, ((Integer)s.pop()).intValue()).
assertEquals(1, ((Integer)s.pop()).intValue()).
assertEquals(null, s.pop()).
}
} |