将一个字符串str的内容颠倒过来,并输出。
数据范围:
import java.util.Scanner; // 注意类名必须为 Main, 不要有任何 package xxx 信息 public class Main { public static void main(String[] args) { Scanner in = new Scanner(System.in); while (in.hasNextLine()) { // 注意 while 处理多个 case StringBuilder b = new StringBuilder(in.nextLine()); System.out.println(b.reverse()); } } }
import java.util.Scanner; // 注意类名必须为 Main, 不要有任何 package xxx 信息 public class Main { public static void main(String[] args) { Scanner in = new Scanner(System.in); // 注意 hasNext 和 hasNextLine 的区别 String a = in.nextLine(); StringBuilder su = new StringBuilder(a); System.out.println(su.reverse().toString()); } }
import java.io.BufferedReader; import java.io.IOException; import java.io.InputStreamReader; // 注意类名必须为 Main, 不要有任何 package xxx 信息 public class Main { public static void main(String[] args) throws IOException { BufferedReader br = new BufferedReader(new InputStreamReader(System.in)); String str = ""; while ((str = br.readLine()) != null) { StringBuilder sb = new StringBuilder(str); sb = sb.reverse(); System.out.println(sb.toString()); } } }
import java.util.Scanner; public class Main{ public static void main(String[] args){ Scanner scan = new Scanner(System.in); String str = scan.nextLine(); StringBuilder reverseStr = new StringBuilder(); for(int i = str.length() - 1; i >= 0; i--){ reverseStr.append(str.charAt(i)); } System.out.println(reverseStr); } }
import java.io.BufferedReader; import java.io.IOException; import java.io.InputStreamReader; /** * 字符逆序 */ public class Main { public static void main(String[] args) throws IOException { BufferedReader bf = new BufferedReader(new InputStreamReader(System.in)); String result = bf.readLine(); char[] chars = result.toCharArray(); for (int a = 0; a < chars.length; a++) { int beginNum = a; int endNum = chars.length - 1 - a; if (endNum < beginNum) { break; } char temp = chars[beginNum]; chars[beginNum] = chars[endNum]; chars[endNum] = temp; } System.out.println(String.valueOf(chars)); } } 利用首尾的位置进行交换