遍历ArrayList-不打印任何内容

Question

所以我需要创建一个ArrayList，只接受那些...

• “等级”低于85％，
• 如果“等级”低于85％，请测试其“规定”
• 如果他们的“调节”> = 0.5，请测试他们的“沟通”
• 如果他们的“交流”等于“平均”或“优秀”

然后将其添加到列表中

我想这就是我的代码在做什么，但它没有打印任何内容。 由于它没有出现任何错误，因此使我相信它并没有真正遍历它。 或者它遍历第一个（不符合条件）并停止，因此将没有任何可打印的内容。 Ive查找了其他示例，并尝试实现和更改一些内容，但仍然无法正常工作。 对我来说，它似乎应该工作，所以我不知道要更改什么。

任何建议将不胜感激！

import java.util.ArrayList;

public class Candidate extends AddressBook {

  private boolean innovation;
  private double grade;
  private double regulation;
  private String communication;

  public Candidate(String fn, String ln, double grade, String comm,
          boolean innov, double reg) {
      super(fn, ln);

      this.grade = grade;
      this.communication = comm;
      this.innovation = innov;
      this.regulation = reg;
}

  public boolean isInnovative() {
      return innovation;
}

  public double getGrade() {
      return grade;
}

  public double getRegulation() {
      return regulation;
}

  public String getCommunication() {
      return communication;
}

public static ArrayList<Candidate> getEligibleCandidates(Candidate[] cands) {
    ArrayList<Candidate> eligibleCandidates = new ArrayList<Candidate>();

    Candidate person = cands[0];

    for (Candidate i : cands) {
        while (i.getGrade() < 85) {
            if (i.getRegulation() >= 0.5) {
                if (i.getCommunication().equals("average")
                        || i.getCommunication().equals("excellent")) {

                    person = i;
                    eligibleCandidates.add(i);

                }
            }

        }

    }

    return eligibleCandidates;
}

public void setCommunication(String comm) {
    this.communication = comm;
}

public void setGrade(double grade) {
    this.grade = grade;
}

public void setInnovation(boolean innov) {
    this.innovation = innov;
}

public void setRegulation(double reg) {
    this.regulation = reg;
}



public static void main(String[] args) {

    Candidate r1 = new Candidate("Elena", "Brandon", 82.30, "poor", true,
            0.5);
    Candidate r2 = new Candidate("Thomas", "Molson", 85.10, "poor", false,
            1.0);
    Candidate r3 = new Candidate("Hamilton", "Winn", 77.77, "average",
            false, 0.8);
    Candidate r4 = new Candidate("Suzie", "Sarandin", 69.93, "average",
            false, 0.0);
    Candidate r5 = new Candidate("Philip", "Winne", 93.03, "average", true,
            1.0);
    Candidate r6 = new Candidate("Alex", "Trebok", 88.61, "poor", true, 0.7);
    Candidate r7 = new Candidate("Emma", "Pivoto", 55.99, "excellent",
            false, 0.8);
    Candidate r8 = new Candidate("John", "Lenthen", 87.49, "excellent",
            true, 0.9);
    Candidate r9 = new Candidate("James", "Lean", 88.00, "excellent",
            false, 0.5);
    Candidate r10 = new Candidate("Jane", "Ostin", 91.20, "average", true,
            0.6);
    Candidate r11 = new Candidate("Emily", "Car", 66.79, "excellent",
            false, 0.3);
    Candidate r12 = new Candidate("Daniel", "", 76.65, "average", true, 0.2);
    Candidate r13 = new Candidate("Neda", "Bazdar", 55.89, "excellent",
            true, 0.5);
    Candidate r14 = new Candidate("Aaron", "Smith", 90.01, "excellent",
            false, 0.3);
    Candidate r15 = new Candidate("Kate", "Hen", 87.9, "poor", false, 0.8);

    Candidate[] cands = { r1, r2, r3, r4, r5, r6, r7, r8, r9, r10, r11,
            r12, r13, r14, r15 };

    ArrayList<Candidate> people = Candidate.getEligibleCandidates(cands);

    System.out.println(people);

}

}

Answer 1

它停止了，因为

for (Candidate i : cands) {
    while (i.getGrade() < 85) {
        if (i.getRegulation() >= 0.5) {
            if (i.getCommunication().equals("average")
                    || i.getCommunication().equals("excellent")) {
                person = i;
                eligibleCandidates.add(i);
            }
        }
    }
}

考虑一下它一旦进入（i.getGrade（）<85），它就不会更改条件的值以使其脱离循环。 这将是无穷无尽的for循环。 您需要将其更改为if语句

for (Candidate i : cands) {
    if (i.getGrade() < 85) {
        if (i.getRegulation() >= 0.5) {
            if (i.getCommunication().equals("average")
                    || i.getCommunication().equals("excellent")) {
                person = i;
                eligibleCandidates.add(i);
            }
        }
    }
}

Answer 2

一旦您的代码进入while (i.getGrade() < 85)它就永远不会退出。 那应该是一个if检查，而不是一个循环。 在该loop内，您永远不会更改要检查的人，因此一旦它成为真，它将永远永远为真。

例如，使用“ Elena”，将执行循环并检查is Elena's grade < 85? 。 既然如此，它将进入循环。 然后，一旦循环完成处理，它将返回循环顶部并检查， is Elena's grade STILL less than 85? ，这是正确的，因为它从未在循环中更改过。

您应该使用if检查，如下所示。

    for (Candidate currentCandidate : cands) {
        if(currentCandidate.getGrade()<85 && currentCandidate.getRegulation() >= 0.5 && (currentCandidate.getCommunication().equals("average") || currentCandidate.getCommunication().equals("excellent"))){
            eligibleCandidates.add(currentCandidate);
        }
    }

Answer 3

它应该是：

if ((i.getGrade() < 85) &&
    (i.getRegulation() >= 0.5) &&
    (i.getCommunication().equals("average") || i.getCommunication().equals("excellent"))) {
        person = i;
        eligibleCandidates.add(i);
    }
  }
}

...而不是while ...