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; } } }