Question

我想弄明白为什么会有这些错误。

我正在制作程序的提示基于：http://puu.sh/lv7ho/2e415d805b.png

我已经完成了这个程序的大部分，我只是遇到了一些我希望得到一些帮助的错误。我为程序的每个功能制作了单独的方法，比如打印，计算和收集输入。

我在第43-45行的错误中为totalTrees，totalSeeds和minSeeds说“找不到符号”。然后第56行我得到了所有三个相同的错误。

这是因为我只在main方法中声明了它们并且需要复制它们。但是，我是一个菜鸟，我不知道如何将数据从getCalculate复制到程序中。我怀疑它与我的getCalculate返回有关。

我的代码：

import javax.swing.JOptionPane;

public class TreeCalc{

public static void main(String[] args){


String[] treeTypes = new String[] {"Fir", "Pine", "Spruce"};
int[] desiredYield = new int [treeTypes.length];
double[] decayRate = new double[] {0.07, 0.12, 0.08};
desiredYield = getYield(decayRate, desiredYield, treeTypes);
getCalculate(decayRate, desiredYield, treeTypes);
printMessage(decayRate, desiredYield, treeTypes);

}

//Asks user to input # of trees for each tree type
public static int[] getYield(double[]decayRate, int[] desiredYield,   String[]treeTypes){
   int index= 0;
   for(int i=0;i < treeTypes.length;i++){
         try{
         desiredYield[index] = Integer.parseInt(JOptionPane.showInputDialog("Please enter your desired yield for: " +treeTypes[i]));
    }catch(NumberFormatException e){
       desiredYield[index]=0;
       JOptionPane.showMessageDialog(null, "Error: Please enter your desired yield for "+treeTypes[i]);                  
       }if (desiredYield[index]<=0){
          JOptionPane.showMessageDialog(null, "Error: Please enter your desired yield for "+treeTypes[i]);
      }else{
          index++;
    }
} 

 return desiredYield;
 }

  //Calculates totals and minimums
 public static int[] getCalculate(double[]decayRate, int[]desiredYield,   String[]treeTypes){
  int totalSeeds =0;
  int totalTrees=0;
  int minSeeds=0;      
  int index=0;
  for(int i=0; i<treeTypes.length;i++){
      minSeeds+=(desiredYield[index] * (decayRate[index]*7))+desiredYield[index];
      totalSeeds+=minSeeds;
      totalTrees+=desiredYield[index];

  }
return desiredYield;
}

 public static void printMessage(double[]decayRate, int[]desiredYield,     String[]treeTypes){
getCalculate(decayRate, desiredYield, treeTypes);

 String treeReport = "Tree Type | Minimum Seeds | Total Seeds | Total Trees ";
for(int i=0; i<treeTypes.length; i++){
  treeReport += "\n"+treeTypes[i] + " " + minSeeds + " " + totalSeeds + " " + totalTrees;
 }
  JOptionPane.showMessageDialog(null, treeReport);
}
}

Answer 1

将这些字段设为静态，并将其从该方法中删除，如此

package treecalc;

import javax.swing.JOptionPane;

public class TreeCalc {

    static int totalSeeds = 0;
    static int totalTrees = 0;
    static int minSeeds = 0;
    static int index = 0;

    public static void main(String[] args) {

        String[] treeTypes = new String[]{"Fir", "Pine", "Spruce"};
        int[] desiredYield = new int[treeTypes.length];
        double[] decayRate = new double[]{0.07, 0.12, 0.08};
        desiredYield = getYield(decayRate, desiredYield, treeTypes);
        getCalculate(decayRate, desiredYield, treeTypes);
        printMessage(decayRate, desiredYield, treeTypes);

    }

//Asks user to input # of trees for each tree type
    public static int[] getYield(double[] decayRate, int[] desiredYield, String[] treeTypes) {
        int index = 0;
        for (int i = 0; i < treeTypes.length; i++) {
            try {
                desiredYield[index] = Integer.parseInt(JOptionPane.showInputDialog("Please enter your desired yield for: " + treeTypes[i]));
            } catch (NumberFormatException e) {
                desiredYield[index] = 0;
                JOptionPane.showMessageDialog(null, "Error: Please enter your desired yield for " + treeTypes[i]);
            }
            if (desiredYield[index] <= 0) {
                JOptionPane.showMessageDialog(null, "Error: Please enter your desired yield for " + treeTypes[i]);
            } else {
                index++;
            }
        }

        return desiredYield;
    }

    //Calculates totals and minimums
    public static int[] getCalculate(double[] decayRate, int[] desiredYield, String[] treeTypes) {

        for (int i = 0; i < treeTypes.length; i++) {
            minSeeds += (desiredYield[index] * (decayRate[index] * 7)) + desiredYield[index];
            totalSeeds += minSeeds;
            totalTrees += desiredYield[index];

        }
        return desiredYield;
    }

    public static void printMessage(double[] decayRate, int[] desiredYield, String[] treeTypes) {
        getCalculate(decayRate, desiredYield, treeTypes);

        String treeReport = "Tree Type | Minimum Seeds | Total Seeds | Total Trees ";
        for (int i = 0; i < treeTypes.length; i++) {
            treeReport += "\n" + treeTypes[i] + " " + minSeeds + " " + totalSeeds + " " + totalTrees;
        }
        JOptionPane.showMessageDialog(null, treeReport);
    }
}

或者您可以创建一个名为Result的类，以便您可以在getCalculate()中一次性返回所有值，如：

public class Result {

int[] desiredYield;
int totalSeeds;
int totalTrees;
int minSeeds =;

public Result(){

//construct a result

}

//getters and setter

}

然后将getCalculate()的返回类型更改为结果并返回Result而不只是desiredYeilds，然后将该结果传递给printMessage()，这样您就可以可以在Result

的一个实例中访问所有这些值

调用方法和数组

1 个答案: