Java (1)寻找一堆数字中只出现一次的数字 (2)统计一堆文件后缀名共有几种类型(即统计一堆数字中出现过那几个数字)

//*************(1)寻找一堆数字中只出现一次的数字***********

package cn.nrsc.test1;

import java.util.ArrayList;

//设计一个方法，传入一个int类型数组，输出这个数组中只出现一次的数字。
public class OnlyOnce {

    public static void main(String[] args) {
        int[] a = { 1, 2, 5, 0, 5, 100, 3, 10, 1, 2, 3, 6, 8, 9, 5, 4, 7 };
        Array(a);
    }

    public static void Array(int[] a) {
        int index = 0;
        for (int i = 0; i < a.length; i++) {
            for (int j = 0; j < a.length; j++) {
                if (i == j) {
                    continue;
                }
                if (a[i] == a[j]) {
                    index = -1;
                    break;
                }
            } // for
            if (index != -1) {
                System.out.print(a[i] + "  ");
            }
            index = 0;
        } // for
    }// main

}


//**(2)统计一堆文件后缀名共有几种类型(即统计一堆数字中出现过那几个数字)**

package cn.nrsc.test1;

import java.util.ArrayList;

//import javax.swing.event.ListSelectionEvent;

public class HouZui {

    public static void main(String[] args) {
        String[] str = new String[7];
        str[0] = "test.txt";
        str[1] = "demo.java";
        str[2] = "test.java";
        str[3] = "score.doc";
        str[4] = "score.ppt";
        str[5] = "score.java";
        str[6] = "score.doc";

        ArrayList<String> list = new ArrayList<>();
        ArrayList<String> list2 = new ArrayList<>();
        for (int i = 0; i < str.length; i++) {
            list.add(str[i]);
        } // for

        for (int i = 0; i < list.size(); i++) {
            String str1 = list.get(i);
            String[] str2 = str1.split("\\.");
            list2.add(str2[1]);
            // System.out.println(str2[0] + " +++ " + str2[1]);
            // System.out.println(str2[1]);
        } // for

        for (int i = 0; i < list2.size(); i++) {
            for (int j = i + 1; j < list2.size(); j++) {
                if (list2.get(i).equals(list2.get(j))) {
                    list2.remove(j);
                }
            }
        } // for
            
        System.out.println("集合中共有" + list2.size() + "种文件后缀");
        System.out.println("他们分别为:"+list2);

    }

}

标签：一堆,数字,int,ArrayList,list2,后缀名,++,str,String
来源： https://blog.51cto.com/u_15288542/3030147