州花鸟

Question

这是按原样运行的，但我正在寻找另一种方法来编写它。

import java.util.Scanner;

public class StateBirdAndFlowerProgram {

    public static void main(String args[]) {

      // Begin Scanner for user input later on
      Scanner input = new Scanner( System.in );

       //Begin array of information
      String[][] states={
                        {"Alabama", "Flower: Camelia", "Bird: Northern flicker"},
                        {"Alaska", "Flower: Forget-me-not", "Bird: Willow ptarmigan "},
                        {"Arizona", "Flower: Saguaro cactus blossom", "Bird: Cactus wren "},
                        {"Arkansas", "Flower: Apple blossom", "Bird: Northern mockingbird "},
                        {"Califorina", "Flower: Califorina poppy", "Bird: California quail"},
                        {"Colorado", "Flower: Rocky Mountian columbine", "Bird: Lark bunting"},
                        {"Connecticut", "Flower: Mountain laurel ", "Bird: American robin"},
                        {"Delaware", "Flower: Peach blossom", "Bird: Delaware Blue Hen "},
                        {"Florida", "Flower: Orange blossom ", "Bird: Northern mockingbird "},
                        {"Georgia", "Flower: Cherokee rose ", "Bird: Brown thrasher ", },
                        {"Hawaii", "Flower: Hawaiian hibiscus ", "Bird: Nēnē or Hawaiian goose"},
                        {"Idaho", "Flower: Syringa, mock orange ", "Bird: Mountain bluebird  "},
                        {"Illinois", "Flower: Violet ", "Bird: Northern cardinal "},
                        {"Indiana", "Flower: Peony ", "Bird: Northern cardinal "},
                        {"Iowa ", "Flower: Wild prairie rose ", "Bird: Eastern goldfinch "},
                        {"Kansas", "Flower: Sunflower", "Bird: Western meadowlark"},
                        {"Kentucky", "Flower: Goldenrod ", "Bird: Northern cardinal"},
                        {"Louisiana", "Flower: Magnolia ",  "Bird: Brown pelican "},
                        {"Maine", "Flower: White pine cone and tassel ", "Bird: Black-capped chickadee "},
                        {"Maryland", "Flower: Black-eyed susan ", "Bird: Baltimore oriole"},
                        {"Massachusetts", "Flower: Mayflower ", "Bird: Black-capped chickadee "},
                        {"Michigan", "Flower: Apple blossom",  "Bird: American robin "},
                        {"Minnesota", "Flower:Pink and white lady's slipper ","Bird: Common loon"},
                        {"Mississippi", "Flower: Magnolia", "Bird: Northern mockingbird "},
                        {"Missouri", "Flower: Hawthorn", "Bird: Eastern bluebird "},
                        {"Montana", "Flower: Bitterroot ", "Bird: Western meadowlark "},
                        {"Nebraska", "Flower: Goldenrod", "Bird: Western meadowlark"},
                        {"Nevada", "Flower: Sagebrush ", "Bird: Mountain bluebird "},
                        {"New Hampshire ", "Flower: Purple lilac ", "Bird: Purple finch "},
                        {"New Jersey", "Flower: Violet ", "Bird: Eastern goldfinch "},
                        {"New Mexico", "Flower: Yucca flower", "Bird: Roadrunner  "},
                        {"New York", "Flower: Rose", "Bird: Eastern bluebird "},
                        {"North Carolina", "Flower: Flowering dogwood", "Bird: Northern cardinal "},
                        {"North Dakota", "Flower: Wild prairie rose ", "Bird: Western meadowlark "},
                        {"Ohio", "Flower: carlet carnation ", "Bird Northern cardinal: "},
                        {"Oklahoma", "Flower: Oklahoma rose ",  "Bird: Scissor-tailed flycatcher "},
                        {"Oregon", "Flower: Oregon grape ", "Bird: Western meadowlark "},
                        {"Pennsylvania", "Flower: Mountain laurel", "Bird: Ruffed grouse"},
                        {"Rhode Island", "Flower: Violet", "Bird: Rhode Island Red "},
                        {"South Carolina", "Flower: Yellow jessamine ","Bird: Carolina wren", },
                        {"South Dakota ", "Flower: Pasque flower ", "Bird: Ring-necked pheasant"},
                        {"Tennessee", "Flower: Iris", "Bird: Northern mockingbird ",},
                        {"Texas", "Flower: Bluebonnet sp. ", "Bird: Northern mockingbird "},
                        {"Utah", "Flower: Sego lily", "Bird: California gull "},
                        {"Vermont", "Flower: Red clover ", "Bird: Hermit thrush"},
                        {"Virginia", "Flower: American dogwood", "Bird: Northern cardinal"},
                        {"Washington", "Flower: Coast rhododendron", "Bird: Willow goldfinch "},
                        {"West Virginia", "Flower:Rhododendron", "Bird: Northern cardinal "},
                        {"Wisconsin", "Flower: Wood violet ", "Bird: American robin "},
                        {"Wyoming", "Flower: Indian paintbrush ", "Bird: Western meadowlark "}};
      // While loop to search through array
      while(true) {

           // Request user input
           System.out.println("Enter a state: ");
           // Capture user input
           String stateName =input.nextLine();
           // exit statement
           if(stateName.equalsIgnoreCase("None"))
                // Exit program
                System.exit(0);

           else {
                // For loop to search through array
                for(int row=0,column=0;row<states.length;row++) {
                     // If statement for matching input string to array data
                     if(states[row][0].equalsIgnoreCase(stateName)) {
                          // Print bird information
                          System.out.println("Bird: " + states[row][column+1]);
                          // Print Flower information
                          System.out.println("Flower: " + states[row][column+2] + "\n");

                     } // end if

                } // end for

           } // end else

      } // end while

 } // end main
} // end class

Answer 1

Bug

我运行了您的代码，得到了如下输出：

进入一个州:印第安纳鸟:花:牡丹花:鸟:北红衣主教

所以，有两件事：

(一)您的列的顺序不对或标签不正确；

2)你的标签是复制的。它们已经存在于您的数据中(这是不寻常的)，因此您可以从print子句中删除标签。

                      System.out.println(states[row][column+1]);
                      System.out.println(states[row][column+2] + "\n");

然而，在更现实的情况下，标签很可能不会与数据一起包括在内。

更好的UI

您的用户输入不是很直观。接受这一系列的输入：

进入一个州:波士顿进入一个州；加拿大进入一个州:42个进入一个州:无

如果在数组中找不到输入的值，那么更改代码以添加到达的System.out.println("State not found: " + stateName)应该是非常容易的。

此外，考虑添加此System.out.println("Enter a state: (or None to exit)");作为退出程序的方式并不明显。

代码注释

我不确定是否对每一行代码进行注释是老师的要求，但大多数程序员会发现这是非常过分的。在生产代码中，您不经常看到代码注释(除了特定于语言的构造(如JavaDoc) )，因为代码应该为自己说明它所做的事情。如果某个代码背后的推理不清楚，通常只需要添加注释。

这些措施特别过分：

} // end if } // end for } // end else } // end while } // end main } // end class

实际上，在许多情况下，在需要变量之前，最好不要声明变量。如果您必须始终上下查找以查找变量声明的使用情况，那么代码就更难理解了。它还使将变量保持在正确的范围更容易。

//开始扫描，以便稍后在Scanner = new Scanner( System.in )上输入用户；

我相信其他人会找到很多其他的东西来批评和帮助您编写代码，这只是一个开始。

Answer 2

使用Enum

您的数据集肯定是我会使用枚举的东西，如果不是csv的话。

下面是一个简洁的例子，说明这是什么样子的：

enum States {
    AL("Alabama", "Camelia", "Northern Flicker"),
    NY("New York", "Rose", "Eastern Bluebird");

    private final String name;
    private final String flower;
    private final String bird;

    States(String name, String flower, String bird) {
        this.name = name;
        this.flower = flower;
        this.bird = bird;
    }

    @Override
    public String toString() {
        return name;
    }

    public String initials() {
        return name();
    }

    public String flower() {
        return flower;
    }

    public String bird() {
        return bird;
    }
}

下面是一个使用上述方法的示例：

import java.util.Scanner;

public class Tester {
    public static void main(String[] args) {
        Scanner input = new Scanner(System.in);

        System.out.println("Enter a state's name or initials to look for:");
        String userSelection = input.nextLine();

        // search through the enum
        for (States state : States.values()) {
            if (userSelection.equalsIgnoreCase(state.toString())
            || userSelection.equalsIgnoreCase(state.initials())) {
                System.out.println(
                    state.toString() + "'s bird is the " + state.bird()
                    + " and their flower is: " + state.flower()
                );
                break;
            }
        }

        /* You can extract the above into a method that returns true or false
           and  if false tells the user their entry was invalid/doesn't exist */
    }
}

Answer 3

当我看到这样的东西时，想到了两件事。不过，两者都归结为封装。第一个想法是创建一个State类，其中有一个花，并在它上有一个鸟巢属性。然后，你可以简单地列出这些国家的名单，并适当地进行过滤。

static List<U_S_State> usStates;
static {
    usStates = new ArrayList<U_S_State>();
    usStates.add(new U_S_State("Alabama", "Flower: Camelia", "Bird: Northern flicker"));
}
//pre java 8, comparable needed on U_S_State
public void GetInfo1(String stateName){
    int index = usStates.indexOf(new U_S_State(stateName));
    if (index == -1){//not found
        return;
    }

    U_S_State state = usStates.get(index);
    System.out.println("Bird: " + state.getStateBird());
    System.out.println("Flower: " + state.getStateFlower() + "\n");
}
//Using java8 stream comparable not needed on U_S_State
public void GetInfo2(String stateName){
    if(!usStates.stream().anyMatch(s->s.getStateName()==stateName))
        return;

    U_S_State state = usStates.stream()
            .filter(s->s.getStateName() == stateName)
            .findFirst().get();

    System.out.println("Bird: " + state.getStateBird());
    System.out.println("Flower: " + state.getStateFlower() + "\n");
}

public class U_S_State implements Comparable<U_S_State>{
    private final String stateFlower;
    private final String stateBird;
    private final String stateName;
    private String stateAbbreviation;

    public U_S_State(String stateName){
        this(stateName, "", "");
    }
    public U_S_State(String stateName, String stateFlower, String stateBird) {
        this.stateFlower = stateFlower;
        this.stateBird = stateBird;
        this.stateName = stateName;
    }

    public String getStateAbbreviation() {
        return stateAbbreviation;
    }

    public void setStateAbbreviation(String stateAbbreviation) {
        this.stateAbbreviation = stateAbbreviation;
    }

    public String getStateName() {
        return stateName;
    }

    public String getStateBird() {
        return stateBird;
    }

    public String getStateFlower() {
        return stateFlower;
    }

    @Override
    public int compareTo(U_S_State o) {
        return o.stateName.compareTo(this.stateName);
    }
}

请注意，在名字(甚至命名约定)方面，这可能不是最好的选择，但这确实给了您和去哪里的想法。创建一个可以将自己与他人相比的类。我们只对比较各州的名字感兴趣。实现Comparable<T>对于list是很重要的，因为它是您将如何搜索一个项目前java 8。使用java 8，您可以使用流和lambda的。如果你理解他们方便。这是我的建议。