Question

我正在尝试调试我的程序。要查看它出错的地方，我需要查看输出。但是因为它无限期地使用递归，所以停止程序的唯一方法是重新编译擦除输出。我该如何调试？

我正在调用DTNode。

这是我的班级：

package DecisionTree;

public class DTNode {

    Instance[] instances;
    double cutoff;
    DTNode left, right;

    public DTNode (Instance[] instance, int l, int r) {
      this.instances = instance;
      int i;
      int j = 0;
      int k = 0;
      int getIndex;
      double[] cutoff = new double[instance.length];
      double[] entropy = new double[instance.length];
      int[] split = new int[instance.length];
      double smallestEntropy;

      for(i=0; i<r; i++) {
        if(instance[i].label != instance[i+1].label) {
          cutoff[j] = (instance[i].attribute + instance[i+1].attribute)/2;
          split[j] = i;
          System.out.println("Cutoff is: " + cutoff[j] + ". Split is: " + split[j]);
          j++;
        }
      }

      for(k=0; k<j; k++) {
        entropy[k] = calcEntropy(instance, l, cutoff[k], r);
        System.out.println(entropy[k]);
      }

      smallestEntropy = entropy[0];
      getIndex = split[0];
      for(k=1; k<j; k++) {
        if (entropy[k] < smallestEntropy) {
          smallestEntropy = entropy[k];
          getIndex = k;
        }
      }
      System.out.println(getIndex + "   " + entropy[getIndex]);
      if((r - l) == 0 || j == 0) {
        this.left = null;
        this.right = null;
      }
      else{
        this.left = new DTNode(instance, l, getIndex);
        this.right = new DTNode(instance, getIndex+1, r);
      }
    }

    public double calcEntropy(Instance[] inst, int a, double b, int c) {
      int i;
      double leftSideCounter = 0;
      double rightSideCounter = 0;
      double leftTrue = 0;
      double rightTrue = 0;
      double leftSideEntropy = 0;
      double rightSideEntropy = 0;
      double leftTrueFraction;
      double leftFalseFraction;
      double rightTrueFraction;
      double rightFalseFraction;
      double leftTotalFraction;
      double rightTotalFraction;
      double entropy;

      for(i=a; i<=c; i++){
        if(inst[i].attribute < b) {
          leftSideCounter++;
        }
        else {
          rightSideCounter++;
        }
      }

      for(i=0; i<leftSideCounter; i++) {
        if(inst[i].label == true) {
          leftTrue++;
        }
      }

      for(i=(int)leftSideCounter; i<(int)(rightSideCounter+leftSideCounter); i++) {
        if(inst[i].label == true) {
          rightTrue++;
        }
      }


      leftTrueFraction = leftTrue/leftSideCounter;
      leftFalseFraction = (leftSideCounter-leftTrue)/leftSideCounter;

      rightTrueFraction = rightTrue/rightSideCounter;
      rightFalseFraction = (rightSideCounter-rightTrue)/rightSideCounter;

      leftTotalFraction = leftSideCounter/(leftSideCounter+rightSideCounter);
      rightTotalFraction = rightSideCounter/(leftSideCounter+rightSideCounter);

      if(leftTrue == 0 || (leftSideCounter - leftTrue) == 0) {
        leftSideEntropy = 0;
      }
      else{
      leftSideEntropy = -leftTrueFraction*logb2(leftTrueFraction)-leftFalseFraction*logb2(leftFalseFraction);
      }

      if (rightTrue == 0 || (rightSideCounter - rightTrue) == 0) {
        rightSideEntropy = 0;
      }
      else{
      rightSideEntropy = -rightTrueFraction*logb2(rightTrueFraction)-rightFalseFraction*logb2(rightFalseFraction);
      }
      entropy = leftSideEntropy*leftTotalFraction+rightSideEntropy*rightTotalFraction;

      System.out.println(leftTrue);
      System.out.println("leftTrueFraction = " + leftTrueFraction + ". leftFalseFraction = " + leftFalseFraction);
      System.out.println("rightTrueFraction = " + rightTrueFraction + ". rightFalseFraction = " + rightFalseFraction);
      System.out.println("leftTotalFraction = " + leftTotalFraction + ". rightTotalFraction = " + rightTotalFraction);
      System.out.println("leftSideEntropy = " + leftSideEntropy + ". rightSideEntropy = " + rightSideEntropy);
      return entropy;
    }

    public double logb2(double b) {
      return Math.log(b)/Math.log(2);
    }
}

Answer 1

所有主要IDE都带有调试功能。您可以使用这些调试器轻松调试java文件。

以下是Debugging with eclipse的教程。
如何在intelliJ
如何在netbean
Java本机调试器link here。

您还可以在线查找大量视频。只需搜索Java调试。

如何使用无限循环调试程序？

1 个答案: