題目:
1. 給定一個字符串,判斷該字符串中是否包含某個子串.若是包含,求出子串的全部出現位置.
如:"abcbcbabcb34bcbd"中,"bcb"子串的出現位置爲: 1,7,12.字符串和子串均由用戶輸入java
2.給定一個長度,隨機產生一個該長度的字符串,由大寫,小寫字母以及數字組成
Java中隨機數的生成:
java.util.Random r = new java.util.Random();
int a = r.nextInt(100): a 0-99的隨機數dom
3.給定一個由數字組成的字符串,如:"1239586838923173478943890234092",統計
出每一個數字出現的次數blog
答案以下:字符串
package Chp10; import java.util.HashMap; import java.util.Map; import java.util.Random; import java.util.Scanner; import java.util.Set; public class TestString2 { public static void Method_One() { Scanner s = new Scanner(System.in); System.out.println("請輸入一個父串"); String str = s.next(); System.out.println("請輸入一個子串"); String str1 = s.next(); int stat = 0; while (true) { int i = str.indexOf(str1,stat); if (i==-1) { break; } System.out.println(i); stat = i+str1.length(); } } public static void Method_Two() { System.out.println("請輸入一個長度"); Scanner s = new Scanner(System.in); int n = s.nextInt(); char[] cs = new char[n]; Random random = new Random(); for (int i = 0; i < n; i++) { int a = random.nextInt(62); if(a>=0 && a<=25) { a+=65; } else if (a>25 && a<=51) { // 97 - 26 = 71 a+=71; } else { // 52-48 = 4 a-=4; } cs[i] = (char)a; } System.out.println(cs); } public static void Method_Three() { Scanner scanner = new Scanner(System.in); String string = scanner.next(); int[] c = new int[10]; for (int i = 0; i < string.length(); i++) { char c1 = string.charAt(i); //48-57 int a = c1-48; // 類型轉換 c[a]++; } for (int i = 0; i < c.length; i++) { System.out.println(i+" 出現的次數: "+c[i]); } System.out.println("=========方法二=========="); String s = "12548954231351486214894562"; char[] ch = s.toCharArray(); Map<Character, Integer> map = new HashMap<Character, Integer>(); Set<Character> set = map.keySet(); for (int i = 0; i < ch.length; i++) { if (set.contains(ch[i])) // 判斷map中已經有的char值 { map.put(ch[i], map.get(ch[i])+1); } else { map.put(ch[i], 1); // 第一次放入map中 } } Set<Character> set2 = map.keySet(); for (Character character : set2) { System.out.println(character+"=========="+map.get(character)); } } public static void main(String[] args) { System.out.println("第一題以下:"); Method_One(); System.out.println("第二題以下:"); Method_Two(); System.out.println("第三題以下:"); Method_Three(); } }