Counter c1 = new Counter("ones");
c1.increment();
Counter c2 = c1;
c2.increment();
StdOut.println(c1);
课程代码链接：https ://introcs.cs.princeton.edu/java/33design/Counter.java
public class Counter implements Comparable<Counter> {
private final String name; // counter name
private final int maxCount; // maximum value
private int count; // current value
// create a new counter with the given parameters
public Counter(String id, int max) {
name = id;
maxCount = max;
count = 0;
}
// increment the counter by 1
public void increment() {
if (count < maxCount) count++;
}
// return the current count
public int value() {
return count;
}
// return a string representation of this counter
public String toString() {
return name + ": " + count;
}
// compare two Counter objects based on their count
public int compareTo(Counter that) {
if (this.count < that.count) return -1;
else if (this.count > that.count) return +1;
else return 0;
}
// test client
public static void main(String[] args) {
int n = Integer.parseInt(args[0]);
int trials = Integer.parseInt(args[1]);
// create n counters
Counter[] hits = new Counter[n];
for (int i = 0; i < n; i++) {
hits[i] = new Counter(i + "", trials);
}
// increment trials counters at random
for (int t = 0; t < trials; t++) {
int index = StdRandom.uniform(n);
hits[index].increment();
}
// print results
for (int i = 0; i < n; i++) {
StdOut.println(hits[i]);
}
}
}
书上说会打印“2ones”，过程如上图所示。但我无法得到它。在我看来，c1 添加所以它的对象添加，所以我们得到“2”；然后将 c1 复制到 c2，c2 也得到“2”。随着 c2 添加，对象将转向未知的下一个网格。打印 c1 时，我认为我们应该得到“2”而不是“2ones”。那么我的流程有什么问题？提前致谢。