Java基础之二维数组的回顾

class ArrayWork {
 
    /*
    *    二维数组的复习!
    *
    *    2014年4月2日 21:45:50
    *
    *
    *
    **/
 
    public static void main(String[] args){
 
        int [] arr = {2,4,4,3,64,85,84,3,24,89,4};
 
        System.out.println("-------------------------------");
 
        //找出整型数组的是2倍数的数有几个
        int count = 0;
        for (int i = 0;i<arr.length ;i++ ){
            if (arr[i] % 2 == 0){
                count++;
            }
        }
        System.out.println("数组中2的倍数: " + count + "个");
 
        System.out.println("-------------------------------");
 
        boolean bo = false;
        for (int i = 0;i<arr.length ;i++ ){
            if (arr[i] % 2 == 0){
                bo = true;
            }
        }
        if (bo){
            System.out.println("存在!");
        }else{
            System.out.println("不存在!");
        }
        for (int i = 0;i<arr.length ;i++ ){
            System.out.print(arr[i]+" , ");
        }
 
        System.out.println();
        System.out.println("-------------------------------");
        int star = arr[0];
 
        for (int i = 0;i<arr.length-1;i++ ){
            arr[i]=arr[i+1];
        }
 
        arr[arr.length-1]=star;
 
        for (int i = 0;i<arr.length ;i++ ){
            System.out.print(arr[i]+" , ");
        }
 
        System.out.println();
        System.out.println("-------------------------------");
 
        boolean boo = false;
        for (int i = 0;i<arr.length ;i++ ){
            if (arr[i] % 5 == 0){
                System.out.println(arr[i]);
                boo = true;
                break;
            }
        }
        if (boo==false){
            System.out.println("不存在!");
        }
 
        System.out.println("-------------------------------");
        //改变数组元素值，将一个整型数组里下标是偶数的元素都乘3
        for (int i= 0;i<arr.length ;i++ ){
            if (i%2==0){
                arr[i]=arr[i]*3;
            }
        }
        for (int i = 0;i<arr.length ;i++){
            System.out.print(arr[i]+" , ");
        }
        System.out.println();
 
        System.out.println("-------------------------------");
        //改变数组元素值，将一个整型数组里下标是奇数的元素都加3
        for (int i= 0;i<arr.length ;i++ ){
            if (i%2!=0){
                arr[i]=arr[i]+3;
            }
        }
        for (int i = 0;i<arr.length ;i++){
            System.out.print(arr[i]+" , ");
        }
        System.out.println();
 
        System.out.println("-------------------------------");
        //一个整型数组，有10个元素，打印出低于数组元素平均值的元素
        int brr []  = {2,3,4,8,6,5,4,1,32,5};
        int sun = 0;
        for (int i = 0;i<brr.length ;i++ ){
            sun += brr[i];
        }
        for (int i = 0;i<brr.length ;i++ ){
            if (brr[i] < sun / brr.length){
                System.out.print(brr[i] + " , ");
            }
        }
        System.out.println();
 
        System.out.println("-------------------------------");
        //将数组中第一个元素移到最后数组末尾,其余数据依次往前平移一个位置。
        for (int i = 0;i<arr.length ;i++ ){
            System.out.print(arr[i]+" , ");
        }
 
        System.out.println();
 
        int star2 = arr[0];
 
        for (int i = 0;i<arr.length-1;i++ ){
            arr[i]=arr[i+1];
        }
 
        arr[arr.length-1]=star2;
 
        for (int i = 0;i<arr.length ;i++ ){
            System.out.print(arr[i]+" , ");
        }
 
        System.out.println();
 
        System.out.println("-------------------------------");
 
        boolean bos = false;
        for (int i = 0;i<arr.length ;i++ ){
            if (arr[i] % 2 == 0){
                bos = true;
            }
        }
        if (bos){
            System.out.println("存在!");
        }else{
            System.out.println("不存在!");
        }
 
        System.out.println("-------------------------------");
        //一个整型数组，找出最大数所在位置
        int big = arr[0];
        int count0 = -1;
        for (int i = 0;i<arr.length ;i++ ){
            if (arr[0]<arr[i]){
                arr[0]= arr[i];
                count = i;
            }
        }
        System.out.println("max下标: "+ count);
 
        System.out.println("-------------------------------");
        //一个整型数组，找出最小数所在位置，并将它与第一个数对调位置
        //int crr [] = {5,4,5,6,1,3,2,4,8,85,3,4};
 
        int start = arr[0];
 
        for (int i = 0;i<arr.length ;i++ ){
            System.out.print(arr[i]+" , ");
        }
 
        System.out.println();
 
        int count1 = -1;
 
        for (int i = 0;i<arr.length ;i++ ){
            if (arr[0]>arr[i]){
                arr[0]= arr[i];
                count1 = i;
            }
        }
 
        arr[count1] = start;
 
        for (int i = 0;i<arr.length ;i++ ){
            System.out.print(arr[i]+" , ");
        }
 
        System.out.println();
 
        System.out.println("-------------------------------");
        //查找数组中是否有等于 5 这个元素，有则返回这个元素在数组中的位置；没有，则返回 -1
        int crr [] = {5,4,5,6,1,3,2,4,8,85,3,4};
        int vart  = -1;
        for (int i = 0;i<crr.length ;i++){
            if (crr[i]==5){
                vart = i;
            }
        }
        System.out.println(vart);
 
        System.out.println("-------------------------------");
        //输出数组的前n的值，n是一个变量
        int suru = 200;
        for (int i = 0;i<arr.length ;i++ ){
            if (arr[i]<suru){
                System.out.print(arr[i] + " , ");
            }
        }
        System.out.println();
 
        System.out.println("-------------------------------");
        //删除数组中下标值是k的元素
        int drr []={5,2,2,4,5,6};
        int sd = 3;
        for (int i = sd; i<drr.length-1;i++ ){
            drr[i] = drr[i+1];
        }
        for (int i = 0;i<drr.length-1 ;i++ ){
            System.out.print(drr[i]+" , ");
        }
        System.out.println();
        System.out.println("-------------------------------");
        //定义一个整型数组，将一个数插在数组元素的末尾形成新的数组。输出新数组
        int err [] = {5,2,2,4,5,6,324,23};
        int frr [] = new int [err.length+1];
 
        for (int i = 0;i<err.length ;i++ ){
            frr[i]= err[i];
        }
        frr[frr.length-1] = suru;
 
        for (int i = 0;i<frr.length ;i++ ){
            System.out.print(frr[i]+" ,");
        }
        System.out.println();
        System.out.println("-------------------------------");
        //定义两个数组，将这两个数组合并形成新的数组，打印新数组
        int grr []={2,1,5,6};
        int hrr []={3,5,6,7,4};
        int irr []=new int [grr.length+hrr.length];
        for (int i = 0;i<grr.length ;i++ ){
            irr[i]=grr[i];
        }
        for (int i = 0;i<hrr.length ;i++ ){
            irr[grr.length+i]=hrr[i];
        }
        for (int i = 0;i<irr.length ;i++ ){
            System.out.print(irr[i]+" ,");
        }
 
        System.out.println();
        System.out.println("-------------------------------");
        //16.定于1001班一个数组，里面存放大家的英语成绩，
        //       (1)统计不及格人数，并打印他们的分数，
        //       (2)统计成绩在全班平均分及平均分之上的学生人数，并打印他们的分数；
        //       (3)统计各分数段的学生人数及所占的百分比。分数段(0到30,30到60，60到80,80到90,90到100)
        int jrr [] = {84,92,15,38,79,94,68,15,37,87,95,48,68,75,90,80};
        int count2 = 0;
        int count3 = 0;
        int sum = 0;
        for (int i  = 0; i<jrr.length; i++){
            sum += jrr[i];
            if (jrr[i]<60){
                System.out.print(jrr[i]+" , ");
                count2 ++;
            }
        }
 
        System.out.println("一共: "+ count2 +" 人");
        System.out.println("平均分: "+sum/jrr.length);
        System.out.println("下面是高于平均分的分数");
 
        for (int i = 0;i<jrr.length ;i++ ){
            if (jrr[i]>=sum/jrr.length){
                System.out.print(jrr[i]+" , ");
                count3++;
            }
        }
        System.out.println();
        System.out.println("高于平均分的人数有: "+ count3+" 人");
 
        double g1 = 0;//90到100
        double g2 = 0;//80到90
        double g3 = 0;//60到80
        double g4 = 0;//30到60
        double g5 = 0;//0到30
        for (int i = 0;i<jrr.length ;i++ ){
            if (90<=jrr[i] && jrr[i]<=100){
                g1++;
            }else if (80<=jrr[i] && jrr[i]<90){
                g2++;
            }else if (60<=jrr[i] && jrr[i]<80){
                g3++;
            }else if (30<=jrr[i] && jrr[i]<60){
                g4++;
            }else if (0<=jrr[i] && jrr[i]<30){
                g5++;
            }
        }
 
        double dou1 = (g1/jrr.length)*100 ;
        double dou2 = (g2/jrr.length)*100 ;
        double dou3 = (g3/jrr.length)*100 ;
        double dou4 = (g4/jrr.length)*100 ;
        double dou5 = (g5/jrr.length)*100 ;
 
        System.out.println("90到100 : "+g1 +" 人, 占百分比: "+ dou1+ "%");
        System.out.println("90到100 : "+g2 +" 人, 占百分比: "+ dou2+ "%");
        System.out.println("90到100 : "+g3 +" 人, 占百分比: "+ dou3+ "%");
        System.out.println("90到100 : "+g4 +" 人, 占百分比: "+ dou4+ "%");
        System.out.println("90到100 : "+g5 +" 人, 占百分比: "+ dou5+ "%");
 
        System.out.println("-------------------------------");
        // 数组
        int tab[]={10,15,20,25,30,35,40,45,50,55} ;
        int tabl = 30;
        //    设计一个程序
        //    比如输入30，要输出4，输入10要输出0，输入55要输出9，也就是tab的下标
        for (int i = 0;i<tab.length ;i++ ){
            if (tabl == tab[i]){
                System.out.println(i);
            }
        }
 
        System.out.println("-------------------------------");
        //统计整型数组中的偶数个数
        int tabe[]={10,15,20,25,30,34,40,45,50,55} ;
        int count5 =0;
        for (int i = 0; i<tabe.length; i++){
            if (tabe[i]%2==0){
                count5++;
            }
        }
        System.out.println(count5 );
 
        System.out.println("-------------------------------");
        //输出数组中的元素 ，每3个元素一行
        int taba[]={10,15,20,25,30,34,40,45,50,55} ;
        int count6 =0;
        for (int i = 0; i<taba.length; i++){
            if (count6 % 3 == 0){
                System.out.println();
            }
            System.out.print(taba[i]+" , ");
            count6++;
        }
        System.out.println();
 
        System.out.println("-------------------------------");
        //计算整型数组a中的最大值及其所在的下标。
        int tabs[]={10,15,20,25,55,30,34,40,45,50} ;
        int count7 =tabs[0];
        int count8 = -1;
        for (int i = 0; i<tabs.length; i++){
            if (count7 < tabs[i]){
                count7 = tabs[i];
                count8 = i;
            }
        }
        System.out.println("最大值: "+count7 + "   下标: "+count8);
 
        System.out.println("-------------------------------");
        //定义一个字符串数组，把数组中的每个元素相加后输出
        String dasf [] = {"h","e","l","l","o","w","o","r","d"};
        for (int i = 0;i<dasf.length ;i++ ){
            System.out.print(dasf[i]);
        }
        System.out.println();
 
        System.out.println("-------------------------------");
        //定义一个字符串数组，将其倒序输出\
        String hello [] = {"h","e","l","l","o","w","o","r","d"};
        for (int i = hello.length-1;i>=0 ;i-- ){
            System.out.print(hello[i]);
        }
        System.out.println();
        System.out.println("-------------------------------");
        //有一个字符串数组 ，将数组中每个元素倒转，如 var x=new Array("a","b","c","d") 倒
        //    转后x数组变成了("d","c","b","a")
        String hello1 [] = {"h","e","l","l","o","w","o","r","d"};
        String hello2 [] = new String[hello1.length];
        int jsss = 0;
        for (int i = hello.length-1;i>=0 ;i-- ){
            hello2[jsss] = hello1[i];
            jsss++;
        }
        for (int i = 0;i<hello2.length ;i++ ){
            System.out.print(hello2[i]);
        }
 
        System.out.println();
        System.out.println("-------------------------------");
        //有一个字符串数组，分别统计其相同元素的个数并输出 如数组
            //("a","b","a","d","b","b")  则输出a 2个  b 3个 d 一个（本题属于高难度题目）
        String string []= {"a","b","a","d","b","b"};
        int coun1 = 0;
        int coun2 = 0;
        int coun3 = 0;
        for (int i = 0;i<string.length ;i++ ){
            if (string[i].equals("a")){
                coun1 ++;
            }else if (string[i].equals("b")){
                coun2 ++;
            }else if (string[i].equals("d")){
                coun3 ++;
            }
        }
        System.out.println("a: "+ coun1 + "    b: "+coun2 + "    d: "+coun3);
 
        System.out.println("-------------------------------");
        //有两个长度相同的字符串数组，判断这两个数组中的对应元素是否完全相同，如果完全相
        //    同则输出"呵呵，我爱死你了，怎么搞得跟我一样"，如果有不相同
        //       则把那些不相同的元素打印出来 如("a","b","c")和("a","b","d")  则 打印 第3个元素
        //    不相同  c与d
        String str1 []= {"a","b","a","d","b","b"};
        String str2 []= {"a","b","a","2","b","b"};
        int co1 = 0;
        for (int i = 0;i<str1.length ;i++ ){
            if (str1[i].equals(str2[i])){
                co1++;
            }else {
                System.out.println("第"+ (i+1) +"个元素不相同"+str1[i]+"与"+str2[i]);
                break;
            }
        }
        if (co1 == str1.length){
            System.out.println("呵呵，我爱死你了，怎么搞得跟我一样");
        }
 
        System.out.println("-------------------------------");
    //    两个字符串数组合并，重复的元素去掉，如("a","b","c")和("a","b","d")合并后的数组
    //        为("a","b","c","d")(高难度)
        String st1 []= {"a","b","c"};
        String st2 []= {"a","b","d"};
        String st3 []= new String [4];
        for (int i = 0;i<st1.length ;i++ ){
            st3[i] = st1[i];
        }
        for (int i = 0;i<st2.length ;i++ ){
            if (st3[i].equals(st2[i])){
 
            }else {
                st3[st1.length] = st2[i];
            }
        }
 
        for (int i = 0;i<st3.length ;i++ ){
            System.out.print(st3[i]+" , ");
        }
        System.out.println();
 
        System.out.println("-------------------------------");
 
        int Int[]={15,20,25,55,30,34,10,40,45,50} ;
        int max_1=Int[0];
        int min_1=Int[0];
        for (int i = 0;i<Int.length ;i++ ){
            if (max_1<Int[i]){
                max_1= Int[i];
            }
            if (min_1>Int[i]){
                min_1=Int[i];
            }
        }
        System.out.println("sum:" + (min_1 + max_1));
 
        System.out.println("-------------------------------");
 
        //有一个整型数组，对数组元素进行排序，从大到小输出 （高难度，属于后面要讲的数组排
        //序内容【（比较交换法、选择法、冒泡法）】，能用你们的方法做出来固然好，做不   出来
        //别把脑想坏了）
        int Intger[]={15,20,25,55,30,34,10,40,45,50} ;
        int ssa = Intger[0];
        for (int i = 0;i<Intger.length ;i++ ){
            for (int j = 0;j<Intger.length ;j++ ){
                if (Intger[i]<Intger[j]){
                    ssa = Intger[j];
                    Intger[j] = Intger[i];
                    Intger[i] = ssa;
                }
            }
        }
        for (int i = 0;i<Intger.length ;i++ ){
            System.out.print(Intger[i]+",");
        }
 
        System.out.println();
        System.out.println("-------------------------------");
        int fblx [] = new int[20];
        fblx[0] = 1;
        fblx[1] = 1;
        for (int i = 2;i<fblx.length ;i++ ){
            fblx[i]=fblx[i-1]+fblx[i-2];
        }
 
        for (int i = 0;i<fblx.length ;i++ ){
            System.out.print(fblx[i]+" ,");
        }
        System.out.println();
        System.out.println("-------------------------------");
        //给定一个数据元素，要求根据这个元素把数组里的该元素删除  如var x="a";有数组 var
            //cc=new Array("a","b","c"),则删除元素a后数组变成了("b","c")(有一定难度)
        String []cc={"a","b","c"};
        String []cc2=new String [cc.length-1];
        int catr = 0;
        for (int i = 0;i<cc.length ;i++ ){
            if (cc[i].equals("a")){
 
            }
        }
        for (int i= catr;i<cc.length-1 ;i++ ){
            cc[i]=cc[i+1];
        }
        for (int i = 0;i<cc2.length ;i++ ){
            cc2[i]=cc[i];
        }
        for (int i = 0;i<cc2.length ;i++ ){
            System.out.print(cc2[i]+" ,");
        }
        System.out.println();
        System.out.println("-------------------------------");
        //将10个数放入到数组，然后再进行从小到大排序后输出。 
 
        int Intge[]={15,20,25,55,30,34,10,40,45,50} ;
        int sa = Intge[0];
        for (int i = 0;i<Intge.length ;i++ ){
            for (int j = 0;j<Intge.length ;j++ ){
                if (Intge[i]<Intge[j]){
                    sa = Intge[j];
                    Intge[j] = Intge[i];
                    Intge[i] = sa;
                }
            }
        }
        for (int i = 0;i<Intge.length ;i++ ){
            System.out.print(Intge[i]+",");
        }
 
        System.out.println();
        System.out.println("-------------------------------");
 
        //将一个数组逆序输出。有20个数字
 
        int Intg[]={15,20,25,55,30,34,10,40,45,50,15,20,25,55,30,34,10,40,45,50} ;
        int seee = Intg[0];
        for (int i = 0;i<Intg.length ;i++ ){
            for (int j = 0;j<Intg.length ;j++ ){
                if (Intg[i]>Intg[j]){
                    seee = Intg[j];
                    Intg[j] = Intg[i];
                    Intg[i] = seee;
                }
            }
        }
        for (int i = 0;i<Intg.length ;i++ ){
            System.out.print(Intg[i]+",");
        }
 
        System.out.println();
 
        System.out.println("-------------------------------");
        //通过输入框输入数组，提示请输入第x个数字，当输入的-1为结束。最后输出这个数组的数据。
        int Inttr[]={15,20,25,55,30,34,10,40,45,50,15,20,25,55,30,34,10,40,45,50} ;
        int sdff = -1;
        for (int i = 0;i<Inttr.length ;i++ ){
            if (i==sdff){
                System.out.println(Inttr[i]);
            }else if (i==-1){
                System.out.println("结束");
                break;
            }
 
        }
        for (int i = 0;i<Inttr.length ;i++ ){
            System.out.print(Inttr[i]+" ,");
        }
        System.out.println();
        System.out.println("-------------------------------");
            //有一个数组a[2,5,9,2,6,3,1,2,5,6,7,8,4,0]，统计这个数字不相同的数字有多少个，它
            //们相同的个数是多少。
        int atery [] = {2,5,9,2,6,3,1,2,5,6,7,8,4,0};
        int xt = 0;
        int bt = 0;
        for (int i = 0;i<atery.length ;i++ ){
            for (int j = 0;j<atery.length ;j++){
                if (atery[i]==atery[j]){
                    xt++;
                }else {
                    bt++;
                }
            }
 
        }
        System.out.println("相同: "+xt/2+"不同: "+bt/12);
 
        System.out.println("-------------------------------");
            //有两个数组a[1,2,6,4,3,7,8,4,5,7],b[12,45,1,2,5,2,6,8,9],同时存在这两个数据的数
            //字有哪些，请输出。
        int szji1 [] = {1,2,6,4,3,7,8,4,5,7};
        int szji2 [] = {12,45,1,2,5,2,6,8,9};
        for (int i = 0;i<szji1.length ;i++ ){
            for (int j = 0;j<szji2.length ;j++){
                if (szji1[i]==szji2[j]){
                    System.out.println(szji1[i]+"和"+szji2[j]);
                }
            }
 
        }
        System.out.println();
        System.out.println("-------------------------------");
        //请输入星期几的第一个字母来判断一下是星期几，如果第一个字母一样，则继续    判断
        //第二个字母。
        String day = "二";
        if (day=="一"){
            System.out.println("星期一");
        }else if (day == "二"){
            System.out.println("星期二");
        }else if (day == "三"){
            System.out.println("星期三");
        }else if (day == "四"){
            System.out.println("星期四");
        }else if (day == "五"){
            System.out.println("星期五");
        }else if (day == "六"){
            System.out.println("星期六");
        }else if (day == "日"){
            System.out.println("星期日");
        }
        System.out.println("-------------------------------");
        //.猴子吃桃问题：猴子第一天摘下若干个桃子，当即吃了一半，还不瘾，又多吃了一个
            //第二天早上又将剩下的桃子吃掉一半，又多吃了一个。以后每天早上都吃了前一天剩下
            //的一半零一个。到第10天早上想再吃时，见只剩下一个桃子了。求第一天共摘了多少。
        System.out.println(fun(1));
    }
    static int fun (int daiy){
        if (daiy  == 10){
            return 1;
        }else{
            return (fun(daiy+1)+1)*2;
        }
    }
}