我希望下面的代码能给我一个子集和一个补充集。
但实际上，结果显示“错误:这不是一个子集!”
it.next() 得到什么以及如何修改我的代码以获得我想要的结果？ 谢谢!
package Chapter8;
import java.util.HashSet;
import java.util.Iterator;
import java.util.Set;
public class Three {
int n;
Set<Integer> set = new HashSet<Integer>();
public static void main(String args[]) {
Three three = new Three(10);
three.display(three.set);
Set<Integer> test = new HashSet<Integer>();
Iterator<Integer> it = three.set.iterator();
while(it.hasNext()) {
test.add(it.next());
three.display(test);
three.display(three.complementarySet(test));
}
}
boolean contains(Set<Integer> s) {
if (this.set.contains(s))
return true;
else
return false;
}
Set<Integer> complementarySet(Set<Integer> s) {
if(this.set.contains(s)){
Set<Integer> result = this.set;
result.removeAll(s);
return result;
}
else {
System.out.println("Error: This is not a subset!");
return null;
}
}
Three() {
this.n = 3;
this.randomSet();
}
Three(int n) {
this.n = n;
this.randomSet();
}
void randomSet() {
while(set.size() < n) {
set.add((int)(Math.random()*10));
}
}
void display(Set<Integer> s) {
System.out.println("The set is " + s.toString());
}
}
最佳答案
您可能想使用 set.containsAll(Collection <?> C)用于检查 Collection(在本例中为 Set)是否是“set”的子集。来自文档:http://docs.oracle.com/javase/7/docs/api/java/util/Set.html#containsAll(java.util.Collection)
boolean containsAll(Collection c)
Returns true if this set contains all of the elements of the specified collection. If the specified collection is also a set, this method returns true if it is a subset of this set.
关于java - Set.contains() 如何决定它是否是一个子集？，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/17824140/