package test;

public class Test02 {

public static void main(String[] args) {

/*

c++中substr有2种用法：

假设：string s = "0123456789";

//只有一个数字5表示从下标为5开始一直到结尾：sub1 = "56789"

string sub1 = s.substr(5); 

//从下标为5开始截取长度为3位：sub2 = "567"

string sub2 = s.substr(5, 3); 

*/

String str = "0123456789";

//

System.out.println(str.substring(1));

System.out.println(str.substring(4,7));

/*

StringBuilder reverse()方法对数据进行反转

*/

StringBuilder sb = new StringBuilder();

for (int i = 0; i < 10; i++) {

sb.append(i);

}

sb.reverse(); //逆序

System.out.println(sb.toString());

int a = '1'-'0';//字符相减，成int型

System.out.println(a);

}

}