【程序41】
題目：海灘上有一堆桃子，五只猴子來分根穷。第一只猴子把這堆桃子憑據(jù)分為五份姜骡，多了一個(gè)，這只猴子把多的一個(gè)扔入海中屿良，拿走了一份圈澈。第二只猴子把剩下的桃子又平均分成五份，又多了一個(gè)尘惧，它同樣把多的一個(gè)扔入海中康栈，拿走了一份，第三喷橙、第四啥么、第五只猴子都是這樣做的，問海灘上原來最少有多少個(gè)桃子贰逾？
public class? Prog41{
??? public static void main(String[] args){
??????? int n;
??????? n = fun(0);
??????? System.out.println("原來有"+n+"個(gè)桃子");
??? }
??? private static int fun(int i){
??????? if(i==5)
? return 1;
??????? else
? return fun(i+1)*5+1;
??? }
}
【程序42】
題目：809*??=800*??+9*??+1
其中??代表的兩位數(shù),8*??的結(jié)果為兩位數(shù)悬荣，9*??的結(jié)果為3位數(shù)。求??代表的兩位數(shù)疙剑，及809*??后的結(jié)果氯迂。
public class? Prog42{
??? public static void main(String[] args){
??????? int n = 0;
??????? boolean flag = false;
??????? for(int i=10;i<100;i++)
? if(809*i==800*i+9*i+1){
? ? flag = true;
? ? n = i;
? ? break;
? }
??????? if(flag)
? System.out.println(n);
??????? else
? System.out.println("無符合要求的數(shù)！");
??? }
}
【程序43】
題目：求0—7所能組成的奇數(shù)個(gè)數(shù)言缤。
public class? Prog43{
??? public static void main(String[] args){
??????? int count = 0;
??????? //聲明由數(shù)字組成的數(shù)
??????? int n = 8;
??????? //一位數(shù)
??????? count = n/2;
??????? //兩位數(shù)
??????? count += (n-1)*n/2;
??????? //三位數(shù)
??????? count += (n-1)*n*n/2;
??????? //四位數(shù)
??????? count += (n-1)*n*n*n/2;
??????? //五位數(shù)
??????? count += (n-1)*n*n*n*n/2;
??????? //六位數(shù)
??????? count += (n-1)*n*n*n*n*n/2;
??????? //七位數(shù)
??????? count += (n-1)*n*n*n*n*n*n/2;
??????? System.out.println("0-7所能組成的奇數(shù)個(gè)數(shù)："+count);
??? }
}
【程序44】
題目：一個(gè)偶數(shù)總能表示為兩個(gè)素?cái)?shù)之和嚼蚀。
import? java.util.Scanner;
public class? Prog44{
??? public static void main(String[] args){
??????? System.out.print("請輸入一個(gè)偶數(shù)：");
??????? Scanner scan = new Scanner(System.in);
??????? int n = scan.nextInt();
??????? scan.close();
??????? if(n%2!=0){
? System.out.println("您輸入的不是偶數(shù)！");
? return;
??????? }
??????? twoAdd(n);
??? }
??? //偶數(shù)分解為素?cái)?shù)之和
??? private static void twoAdd(int n){
??????? for(int i=2;i
??????????? if(isPrime(i)&&isPrime(n-i)){
??????????????? System.out.println(n+"="+(i)+"+"+(n-i));
??????????????? break;
??????????? }
??????? }
??? }
??? //判斷素?cái)?shù)
??? private static boolean isPrime(int m){
??????? boolean flag = true;
??????? for(int i=2;i
??????????? if(m%i==0){
??????????????? flag = false;
??????????????? break;
??????????? }
??????? }
??????? return flag;
??? }
}
【程序45】
題目：判斷一個(gè)素?cái)?shù)能被幾個(gè)9整除
import? java.util.Scanner;
public class? Prog45{
??? public static void main(String[] args){
??????? System.out.print("請輸入一個(gè)數(shù)：");
? Scanner scan = new Scanner(System.in);
? long l = scan.nextLong();
? long n = l;
? scan.close();
? int count = 0;
? while(n>8){
? n /= 9;
? count++;
??? ? }
? System.out.println(l+"能被"+count+"個(gè)9整除管挟。");
??? }
}
【程序46】
題目：兩個(gè)字符串連接程序
public class? Prog46{
??? public static void main(String[] args){
??????? String str1 = "lao lee";
? String str2 = "牛刀";
? String str = str1+str2;
? System.out.println(str);
??? }
}
【程序47】
題目：讀取7個(gè)數(shù)（1—50）的整數(shù)值轿曙，每讀取一個(gè)值，程序打印出該值個(gè)數(shù)的＊僻孝。
import? java.util.Scanner;
public class? Prog47{
??? public static void main(String[] args){
??????? System.out.print("請輸入7個(gè)整數(shù)(1-50)：");
??????? Scanner scan = new Scanner(System.in);
??????? int n1 = scan.nextInt();
??????? int n2 = scan.nextInt();
??????? int n3 = scan.nextInt();
??????? int n4 = scan.nextInt();
??????? int n5 = scan.nextInt();
??????? int n6 = scan.nextInt();
??????? int n7 = scan.nextInt();
??????? scan.close();
??????? printStar(n1);
??????? printStar(n2);
??????? printStar(n3);
??????? printStar(n4);
??????? printStar(n5);
??????? printStar(n6);
??????? printStar(n7);
??? }
??? static void printStar(int m){
??????? System.out.println(m);
??????? for(int i=0;i
? System.out.print("*");
??????? System.out.println();
??? }
}
【程序48】
題目：某個(gè)公司采用公用電話傳遞數(shù)據(jù)导帝，數(shù)據(jù)是四位的整數(shù)，在傳遞過程中是加密的穿铆，加密規(guī)則如下：每位數(shù)字都加上5,然后用和除以10的余數(shù)代替該數(shù)字您单，再將第一位和第四位交換，第二位和第三位交換悴务。
public class? Prog48{
??? public static void main(String[] args){
??????? int n = 1234;
??????? int[] a = new int[4];
??????? for(int i=3;i>=0;i--){
? a[i] = n%10;
? n /= 10;
??????? }
??????? for(int i=0;i<4;i++)
? System.out.print(a[i]);
??????? System.out.println();
??????? for(int i=0;i
? a[i] += 5;
? a[i] %= 10;
??????? }
??????? int temp1 = a[0];
??????? a[0] = a[3];
??????? a[3] = temp1;
??????? int temp2 = a[1];
??????? a[1] = a[2];
??????? a[2] = temp2;
??????? for(int i=0;i
? System.out.print(a[i]);
??? }
}
【程序49】
題目：計(jì)算字符串中子串出現(xiàn)的次數(shù)
public class? Prog49{
??? public static void main(String[] args){
??????? String str = "I come fromCounty DingYuan ProvinceAnHui.";
??????? char[] ch = str.toCharArray();
??????? int count = 0;
??????? for(int i=0;i
??????????? if(ch[i]==' ')
? count++;
??????? }
??????? count++;
??????? System.out.println("共有"+count+"個(gè)字串");
??? }
}
【程序50】
題目：有五個(gè)學(xué)生，每個(gè)學(xué)生有3門課的成績譬猫，從鍵盤輸入以上數(shù)據(jù)（包括學(xué)生號讯檐，姓名，三門課成績）染服，計(jì)算出平均成績别洪，將原有的數(shù)據(jù)和計(jì)算出的平均分?jǐn)?shù)存放在磁盤文件"stud"中。
import? java.io.*;
public class? Prog50{
??? //定義學(xué)生模型
??? String[] number = new String[5];
??? String[] name = new String[5];
??? float[][] grade = new float[5][3];
??? float[] sum = new float[5];
??? public static void main(String[] args)? throws Exception{
??????? Prog50 stud = new Prog50();
??????? stud.input();
??????? stud.output();
??? }
??? //輸入學(xué)號柳刮、姓名挖垛、成績
??? void input() throws IOException{
??????? BufferedReader br = new? BufferedReader(new InputStreamReader(System.in));
??????? //錄入狀態(tài)標(biāo)識
??????? boolean isRecord = true;
??????? while(isRecord){
??????????? try{
? for(int i=0;i<5;i++){
??????????????? ? System.out.print("請輸入學(xué)號：");
??????????????? ? number[i] = br.readLine();
??????????????? ? System.out.print("請輸入姓名：");
??????????????? ? name[i] = br.readLine();
??????????????? ? for(int j=0;j<3;j++){
??????????????????? ? System.out.print("請輸入第"+(j+1)+"門課成績：");
??????????????????? ? grade[i][j] = Integer.parseInt(br.readLine());
??????????????? ? }
??????????????? ? System.out.println();
??????????????? ? sum[i] =? grade[i][0]+grade[i][1]+grade[i][2];
? }
? isRecord = false;
? }catch(NumberFormatException e){
??????????? ???? System.out.println("請輸入一個(gè)數(shù)字痒钝！");
? }
??????? }
??? }
??? //輸出文件
??? void output() throws IOException{
??????? FileWriter fw = new? FileWriter("E://java50//stud.txt");
??????? BufferedWriter bw = new? BufferedWriter(fw);
??????? bw.write("No.? "+"Name? "+"grade1? "+"grade2? "+"grade3? "+"average");
??????? bw.newLine();
??????? for(int i=0;i<5;i++){
? bw.write(number[i]);
? bw.write("?
? "+name[i]);
? for(int j=0;j<3;j++)
? bw.write("?
? "+grade[i][j]);
? bw.write("?
? "+(sum[i]/5));
? bw.newLine();
??????? }
??????? bw.close();
??? }
}
