#千锋逆战班，作业3.03#

7

		String s = "123";
		int i1 = Integer.parseInt(s);
		int i2 = Integer.valueOf(s).intValue();

8

	ABCD

11.12

//11
		String mail = "zhengcg@zparkhr.com";
		System.out.println(mail.substring(0, mail.indexOf('@')));
//12
		int a = mail.indexOf("@");
		int b = mail.lastIndexOf(".");
		if(a >= 0 && b >= 0 && b > a){
			System.out.println("是");
		}else{
			System.out.println("否");
		}

13

		String uuid = java.util.UUID.randomUUID().toString();
		String[] temp = uuid.split("-");
		
		String newUUID = "";
		for(int i = 0; i < temp.length; i++){
			newUUID += temp[i];
		}
		
		System.out.println(uuid);
		System.out.println(newUUID);
		

14

		String s2 = "ABCDEFGhijklmn1234567";
		java.util.Random random = new java.util.Random();
		
		StringBuilder s3 = new StringBuilder();
		for(int i = 0; i < 4; i++){
			int randomIndex = random.nextInt(s2.length());
			String piece = "" + s2.charAt(randomIndex);
			s3 = new StringBuilder(s3.toString()).append(piece);
		}
		System.out.println(s3.toString());

15

		String s4 = "36545453513543635487986654101089";
		char[] c = s4.toCharArray();
		for(int i = 0; i < 10; i++){
			int count = 0;
			for(int j = 0; j < c.length; j++){
				int num = new Integer("" + c[j]); 
				if(num == i){
					count++;
				}
			}
			System.out.println("数字" + i + "出现了" + count + "次");
		}