【剑指Offer】02、替换空格

题目描述

请实现一个函数，将一个字符串中的每个空格替换成“%20”。例如，当字符串为We Are Happy.则经过替换之后的字符串为We%20Are%20Happy。

题解：StringBuffer

 1  public static String replaceSpace(StringBuffer str) {
 2         if(str==null)
 3             return null;
 4         StringBuffer buffer = new StringBuffer();
 5         for(int i=0;i<str.toString().length();i++){
 6             char c = str.charAt(i);
 7             if(String.valueOf(c).equals(" "))
 8                 buffer.append("%20");
 9             else
10                 buffer.append(c);
11         }
12         return buffer.toString();
13     }
14 //测试：
15      public static void main(String[] args) {
16         Scanner scanner = new Scanner(System.in);
17         String string = scanner.nextLine().toString();
18         StringBuffer buffer = new StringBuffer(string);//String变为StringBuffer
19         String s = replaceSpace(buffer);
20         System.out.println(s);
21     }
22 //输入：We Are Happy
23 //输出：We%20Are%20Happy