Enter two strings STR1 and STR2, and count the number of times that the string STR2 appears in STR1.

Enter two strings str1、str2, Statistics string str2 Appear in the str1 Number of times in .

Such as ：str1=”aaas lkaaas” ,str2=” as” , Then output 2.

package labreport7;
import java.util.Scanner;
// Enter two strings  str1、str2, Statistics string  str2  Appear in the  str1  Number of times in .
public class test1 {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in); //  Define the object of scanning keyboard input 
		String s1 = sc.nextLine(); //  Read a line of text from the keyboard 
		String s2=sc.nextLine();
		int i=0;// Index subscript 
		int sum=0;// Number of Statistics 
		while(s1.indexOf(s2,i)!=-1) {// from i Start lookup at index , Returns the index position of the first occurrence of a specified string value in the string . If not, return -1, If yes, the index value is returned 
			i=s1.indexOf(s2,i)+1;// Index value plus one , Then look back 
			sum++;
		}
		System.out.println(sum);
		sc.close();
	}
}

public int indexOf(String str,from Index): Find the index of the first occurrence of the returned character in the string from the specified position , such as “woaizhongguo”indexOf（'o',2） The return value is 6 instead of 1, Neither 11; If not, return -1.

 public int lastIndexOf(String str):  Returns the index of the last occurrence of the specified character in this string , If there is no such character in this string , Then return to  -1.