扫描器输入接受字符串，在 while 循环中跳过所有其他输入. [英] Scanner input accepting Strings skipping every other input inside a while loop.

问题描述

好的，所以代码很简单.通用类ourSet，它接收一些元素，将其放入一个LinkedList 中，并在两个集合上执行一些功能.

Alright, so the code is pretty straight forward. Generic class ourSet, that takes in some elements, puts it in a LinkedList, and does some functions on the two sets.

我的问题实际上与项目的一般概念无关，它更多地出现在我创建的用户输入界面"中.我希望它接收一些字符串并将其添加到集合中，然后在接收字符串EXIT"(全部大写)时退出循环，并对下一个集合执行相同操作.发生的事情是 do while 循环只发送所有奇数的第一个、第三个、第五个…….

My problem is actually quite unrelated the general concept of the project, its more in the "user input interface" I've created. I want it to take in some Strings and add it to the set, then while receiving the string "EXIT" (all caps), to exit the loop, and do the same for the next set. What is happening is that the do while loop is only sending the 1st, 3rd, 5th,.. for all odd numbers.

package set.pkgclass;

import java.util.Scanner; 
import java.util.LinkedList; 


public class SetClass {


public static void main(String[] args) {

    ourSet<String> set1 = new ourSet<String>();  
    ourSet<String> set2 = new ourSet<String>(); 
    Scanner input = new Scanner(System.in); 



    System.out.println("Please enter a string to put in set 1, "
            + "type EXIT (in all caps) to end.");


    do {

        set1.add(input.nextLine());

    }
    while (!"EXIT".equals(input.nextLine()));


    System.out.println("Please enter a string to put in set 2, "
            + "type EXIT (in all caps) to end");

    do {

        set2.add(input.nextLine());
    }
    while (!"EXIT".equals(input.nextLine()));



    ourSet.intersection(set1,set2); 
    ourSet.difference(set1, set2);
    ourSet.union(set1, set2);








     }
  }

class ourSet<T>{




private LinkedList<T> mySet = new LinkedList<>();



public void add(T element){      
    mySet.add(element);
}

public void remove(T element){        
    mySet.remove(element);
}

public boolean membership(T element){        
    if(mySet.contains(element) == true) {
        return true; 
    }

    else {
    return false;
    }
}


public static <T> void union(ourSet<T> s1, ourSet<T> s2){
    System.out.print("The union is: ");
    for (int i=0; i < s1.mySet.size(); i++) {
        T t = s1.mySet.get(i);
        if (!s2.mySet.contains(t)){
            s2.add(t);
            }

    }

    for (int i=0; i < s2.mySet.size(); i++){
        T t = s2.mySet.get(i);
        System.out.print(t+", ");
    }
    System.out.println();  


}
public static <T> void intersection(ourSet<T> s1, ourSet<T> s2){ 
    System.out.print("The intersection is: ");
    for (int i=0; i < s1.mySet.size(); i++) {
        T t = s1.mySet.get(i); 
        if (s2.mySet.contains(t)) {
            System.out.print(t+", ");
        }
    }
    System.out.println();

}

public static <T> void difference(ourSet<T> s1, ourSet<T> s2){
    System.out.print("The difference is: ");
    for (int i=0; i < s1.mySet.size(); i++) {
        T t = s1.mySet.get(i);
        if (!s2.mySet.contains(t)) {
            System.out.print(t+", ");
        }

    }
    System.out.println();  
   }
 }

推荐答案

原因是，你调用了 input.nextLine() 两次:

The reason is, you're calling input.nextLine() twice:

do {

    set1.add(input.nextLine());

}
while (!"EXIT".equals(input.nextLine()));

比 do-while 更简单的方法是 while:

A much easier way than do-while is while:

while (!(String in = input.nextLine()).equals("EXIT")) {
    set1.add(in);
}

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