java text2

 

编写一个方法，输出在一个字符串中，指定字符串出现的次数。

substring()方法:

import java.util.Scanner;

public class Count
{
    public static void main(String[] args)
    {
        Scanner sc = new Scanner(System.in);
        System.out.println("请输入字符串:");
        String str = sc.nextLine();
        System.out.println("请输入指定字符串:");
        String st = sc.nextLine();

        int n = 0;
        for (int i = 0; i <= str.length() - st.length(); i++)
        {
            if (str.substring(i,i+st.length()).equals(st))
            {
                n++;
                i = i+st.length()-1;
            }

        }
        System.out.println("指定字符串出现次数:" + n);
    }
}

 

 

 

 

indexOf()方法:

 

import java.util.Scanner;

public class Count2
{
    public static void main(String[] args)
    {
        Scanner sc = new Scanner(System.in);
        System.out.println("请输入字符串:");
        String str = sc.nextLine();
        System.out.println("请输入指定字符串:");
        String st = sc.nextLine();

        int n = 0, i = 0;
        
        while (i < str.length() - st.length() + 1)
        {
            i = str.indexOf(st, i) + st.length();
            n++;
        }
        System.out.println("指定字符串出现次数:" + n);
    }
}