4.21-4.22+java开发作业

package homework;

import java.util.Scanner;

/**
 * 编程题:
	1: 字符串反转
	  举例：键盘录入”abc”		
		输出结果：”cba”
	

 *
 */

public class BianChengTi1 {
	public static void main(String[] args) {
		
		Scanner sc = new Scanner(System.in);
		System.out.println("请输入一个字符串");
		String s = sc.nextLine();
		StringBuffer sb = new StringBuffer(s) ;
		String str = sb.reverse().toString();
		System.out.println("结果:"+str);
	}
	

}

package homework;

import java.util.Scanner;

/**
 * 2:统计大串中小串出现的次数
  举例：
		在字符串"woaijavawozhenaijavawozhendeaijavawozhendehenaijavaxinbuxinwoaijavagun"
  结果：
 		java出现了5次
 *
 */

public class BianChengTi2 {
	public static void main(String[] args) {
		String str1 ="woaijavawozhenaijavawozhendeaijavawozhendehenaijavaxinbuxinwoaijavagun";
		Scanner sc = new Scanner(System.in);
		System.out.println("请输入需要查找的字符串");
		String str2 = sc.nextLine();
		int sum = sum(str1,str2);
		System.out.println("该字符串出现的次数为:"+sum);
		
		
	}
	public static int sum(String s1,String s2) {
		int sum = 0;
		int index = s1.indexOf(s2);
		while(index!=-1) {
			sum++;
			int start = index + s2.length();
			s1 = s1.substring(start);
			index = s1.indexOf(s2);
		}
		return sum;
	}

}