字符串反转
等于字符从后往前重新拼接
import java.util.Scanner;
/*
-
字符串反转
-
*/
public class test7 {
public static void main(String[] args) {
Scanner sc = new Scanner(System.in);
System.out.println(“请输入一个字符串:”);
String a = sc.nextLine();
String b = reverse(a);
System.out.println(b);
}public static String reverse(String a) {
String s ="" ;
for(int i = 0; i<a.length(); i++){
s += a.charAt(a.length()-1 - i);
}
return s;
}
}
StringBuilder与String相互转换
import java.util.Scanner;
/*
- Stringbuild和String相互转换及StringBulid的方法
- */
public class test8 {
public static void main(String[] args) {
Scanner sc = new Scanner(System.in);
System.out.println(“请输入一个字符:”);
String a = sc.nextLine();
StringBuilder s = new StringBuilder(a);
s.append(" Hello");
s.append(" Java");
System.out.println(s);
s.reverse();
String c = s.toString();
System.out.println©;
}
}
StringBuilder的字符串拼接
/*
- 拼接字符串用StringBuilder
- */
public class test9 {
public static void main(String[] args) {
int[] a ={2,3,4};
StringBuilder st =new StringBuilder();
st.append("[");
for (int i = 0; i < a.length; i++) {
if (i == a.length - 1) {
st.append(a[i]);
} else {
st.append(a[i]);
st.append(",");
}
}
st.append("]");
System.out.println(st);
}
}