TQC+ JAVA 遞迴程式設計 401 ~ 410

TQC+ JAVA6 試題總覽：LINK
Github 備份：LINK

	/* TQC+ JAVA6 - 401 */
	import java.util.Scanner;
	public class JPA401 {
	static Scanner keyboard = new Scanner(System.in);
	public static void main(String args[]) {
	//一開始先輸入一個數字
	System.out.print("Input n (0<=n<=16):");
	int i = keyboard.nextInt();
	//只要不等於結束需要的999便可進入迴圈
	while(i!=999){
	//進入迴圈後再次檢查是否有在0~16的範圍中
	if(i<=16&&i>=0)
	System.out.println(i+"的階乘 = "+R(i));
	//顯示完後，再請使用者輸入一個數字
	System.out.print("Input n (0<=n<=16):");
	i = keyboard.nextInt();
	}
	}
	//遞迴計算方法
	static int R(int i ){
	if(i==0)//當傳入為零時，則回傳1
	return 1;
	else //每次皆會乘上自己的方法，並且傳入i-1的值進入
	return i*R(i-1);
	}
	}

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	/* TQC+ JAVA6 - 402 */
	import java.util.Scanner;
	public class JPA402 {
	public static void main(String[] args) {
	int size = 0;
	do{
	System.out.print("Input n ( 0 <= n <= 16 ):");
	size = new Scanner(System.in).nextInt();
	}while(size>16&&size!=999||size<0&&size!=999);
	while(size!=999){
	//迴圈方法
	int L = facLoop(size);
	System.out.printf("%d的階乘(迴圈) = %d\n",size,L);
	//尾端遞迴
	int T = facTail(size,1);
	System.out.printf("%d的階乘(尾遞迴) = %d\n",size,T);
	do{
	System.out.print("Input n ( 0 <= n <= 16 ):");
	size = new Scanner(System.in).nextInt();
	}while(size>16&&size!=999||size<0&&size!=999);
	}
	}
	//迴圈方法:使用for-loop
	public static int facLoop(int a){
	int sum = 1;
	for(int b=1;b<=a;b++)
	sum = b*sum;
	return sum;
	}
	//尾端遞迴:不斷呼叫自己的方法，進行運算
	public static int facTail(int a,int b){
	if(a==1)
	return b;
	else
	return facTail(a-1,a*b);
	}
	}

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	/* TQC+ JAVA6 - 403 */
	import java.util.Scanner;
	public class JPA403 {
	public static void main(String[] args) {
	int m ,n;
	System.out.print("Input m :");
	m = new Scanner(System.in).nextInt();
	while(m!=999){
	System.out.print("Input n :");
	n = new Scanner(System.in).nextInt();
	int ans0 = 1;
	int ans1 = facTail(m,n,ans0);
	System.out.println("Ans(尾端遞迴):"+ans1);
	int ans2 = facLoop(m,n);
	System.out.println("Ans(迴圈):"+ans2);
	System.out.print("Input m :");
	m = new Scanner(System.in).nextInt();
	}
	}
	//迴圈
	public static int facLoop(int m,int n){
	int sum = 1;//累積要初始化為1
	for(;n>0;n--)
	sum = m*sum;
	return sum;
	}
	public static int facTail(int m,int n,int sum){
	if(n==0)
	return sum;
	else
	return facTail(m,n-1, sum*m);
	//不斷傳入三個變數，第一個變數用來儲存要乘的數，第二個數用來計算還要乘幾次，第三個數用來累積到目前為止的乘積和
	}
	}

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	/* TQC+ JAVA6 - 404 */
	import java.util.Scanner;
	public class JPA404 {
	static Scanner keyboard = new Scanner(System.in);
	public static void main(String args[]) {
	//先請使用者輸入m值
	System.out.print("Input m :");
	int m = keyboard.nextInt();
	//迴圈判斷，m要不等於999才可進入
	while(m!=999){
	//進入迴圈後再請使用者輸入n值
	System.out.print("Input n :");
	int n = keyboard.nextInt();
	//進行最大公因數計算
	System.out.println(R(m,n));
	//迴圈最後在要求使用者輸入下一個迴圈需要的m，若此m在進入下一個迴圈時條件不過，則不進入迴圈了
	System.out.print("Input m :");
	m = keyboard.nextInt();
	}
	}
	//gcd求最大公因數演算法
	static int R(int m,int n){
	if(m%n==0)//如果mod為零時，則找到最大公因數，回傳值
	return n;
	else {//如果mod數不為零時，則把mod得到的數寫入m，再次進行gcd
	int tem = n;
	n = m%n;
	m = tem;
	return R(m,n);
	}
	}
	}

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	/* TQC+ JAVA6 - 405 */
	import java.util.Scanner;
	public class JPA405 {
	static int sum = 0;
	public static void main(String[] args) {
	System.out.print("Input the number :");
	int m = new Scanner(System.in).nextInt();
	int ans =sum2(m);
	System.out.printf("Ans:%d",ans);
	}
	//sum2方法，按照題目給的提示，將程式代入即可
	public static int sum2(int m) {
	if(m==1)
	return 2;
	else {
	//有類似尾端遞迴的概念
	sum = sum + sum2(m-1)+2*m;
	return sum;
	}
	}
	}

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	/* TQC+ JAVA6 - 406 */
	import java.util.Scanner;
	public class JPA406 {
	static Scanner keyboard = new Scanner(System.in);
	public static void main(String args[]) {
	String s;
	System.out.print("Input a String :");
	s = keyboard.nextLine();
	System.out.println(s + " has " + countA(s) + " As");
	System.out.print("Input a String :");
	s = keyboard.nextLine();
	System.out.println(s + " has " + countA(s) + " As");
	}
	//重點在此計算A個數的方法
	public static int countA(String str) {
	//當傳入的字串為空字串時，回傳A的數另為0
	if(str.equals(""))
	return 0;
	//擷取字串的第一個字元，如果為A，則加1，並且利用substring讀出位置1之後的所有字串再傳入countA
	if(str.substring(0,1).equals("A"))
	return 1+countA(str.substring(1));
	//如果第一個字串不等於A，直接利用substring讀出位置1之後的所有字串傳入countA
	else
	return countA(str.substring(1));
	}
	}

view raw TQCplus_JAVA_406 hosted with ❤ by GitHub

	/* TQC+ JAVA6 - 407 */
	import java.util.Scanner;
	public class JPA407 {
	static Scanner keyboard = new Scanner(System.in);
	public static void main(String args[]) {
	String s;
	System.out.print("Input a string of numbers: ");
	s = keyboard.nextLine();
	System.out.printf("尾端遞迴：%d\n", sumTail(s, 0));
	System.out.printf("迴圈：%d\n", sumLoop(s));
	System.out.print("Input a string of numbers: ");
	s = keyboard.nextLine();
	System.out.printf("尾端遞迴：%d\n", sumTail(s, 0));
	System.out.printf("迴圈：%d\n", sumLoop(s));
	}
	//迴圈方法
	static int sumLoop(String s) {
	int ln = s.length();
	int[] num = new int[ln];
	for(int i=0;i<ln;i++)
	num[i]=Integer.parseInt(s.substring(i, i+1));
	int sum =0;
	for(int i=0;i<ln;i++)
	sum+=num[i];
	return sum;
	}
	//尾端遞迴
	static int sumTail(String s,int i){
	if(s.equals(""))//如果傳入的字串為空，回傳累加的i值
	return i;
	else//字串不為空時，則利用substring讀取位置1之後的字串，並傳入
	//後面的i值則將字串的第一個字元讀出轉成數字並累加
	return sumTail(s.substring(1),i+Integer.parseInt(s.substring(0, 1)));
	}
	}

view raw TQCplus_JAVA_407 hosted with ❤ by GitHub

	/* TQC+ JAVA6 - 408 */
	import java.util.Scanner;
	public class JPA408 {
	static Scanner keyboard = new Scanner(System.in);
	public static void main(String args[]) {
	String s, c;
	System.out.print("Input a string: ");
	s = keyboard.nextLine();
	System.out.printf("%s\n", reverse(s));
	System.out.print("Input a string: ");
	s = keyboard.nextLine();
	System.out.printf("%s\n", reverse(s));
	}
	static String reverse(String s )
	{
	if(s.equals(""))//如果傳入字串為空，則回傳s字串
	return s;
	else//將字串的第一個字元從後方累加上去，然後傳入的字串則是透過substring讀出位置1之後的所有字串並傳入reverse
	return reverse(s.substring(1))+s.substring(0, 1);
	}
	}

view raw TQCplus_JAVA_408 hosted with ❤ by GitHub

	/* TQC+ JAVA6 - 409 */
	import java.util.Scanner;
	public class JPA409 {
	static Scanner keyboard = new Scanner(System.in);
	public static void main(String args[]) {
	String s, c;
	System.out.print("Input a string: ");
	s = keyboard.nextLine();
	System.out.print("Input a character: ");
	c = keyboard.nextLine();
	System.out.printf("%s\n", removeChar(s, c));
	System.out.print("Input a string: ");
	s = keyboard.nextLine();
	System.out.print("Input a character: ");
	c = keyboard.nextLine();
	System.out.printf("%s\n", removeChar(s, c));
	}
	static String removeChar(String s,String c)
	{
	if(s.equals(""))//如果傳入的字串為空的話，則回傳空字串
	return "";
	if(s.substring(0, 1).equals(c))//如果傳入字串的第一個字元等於要刪除的字元
	//則利用substring讀取位置1之後的所有字串並再次傳入removeChar
	return removeChar(s.substring(1),c);
	else//如果不等於要刪除的字元，則補回至原本的字串中
	return s.substring(0, 1)+removeChar(s.substring(1),c);
	}
	}

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	/* TQC+ JAVA6 - 410 */
	import java.util.Scanner;
	public class JPA410 {
	static Scanner keyboard = new Scanner(System.in);
	public static void main(String args[]) {
	String s, c1, c2;
	System.out.print("Input a string: ");
	s = keyboard.nextLine();
	System.out.print("Input a character: ");
	c1 = keyboard.nextLine();
	System.out.print("Input another character: ");
	c2 = keyboard.nextLine();
	System.out.printf("%s\n", replace(s, c1, c2));
	}
	static String replace(String s,String c1,String c2){
	if(s.equals(""))//如果傳入的字串為空的話，則回傳空字串
	return "";
	if(s.substring(0, 1).equals(c1))//如果讀出的字元等於要取代的字元，則將新的字元加上去
	return c2+replace(s.substring(1),c1,c2);
	else//如果不等於的話，補回至原本的字串
	return s.substring(0, 1)+replace(s.substring(1),c1,c2);
	}
	}

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TQC+ JAVA6 試題總覽：LINK
Github 備份：LINK

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