【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

  public static String replaceSpace(StringBuffer str) {
         if(str==null)
             return null;
         StringBuffer buffer = new StringBuffer();
         for(int i=0;i<str.toString().length();i++){
             char c = str.charAt(i);
             if(String.valueOf(c).equals(" "))
                 buffer.append("%20");
             else
                 buffer.append(c);
         }
         return buffer.toString();
     }
 //测试：
      public static void main(String[] args) {
         Scanner scanner = new Scanner(System.in);
         String string = scanner.nextLine().toString();
         StringBuffer buffer = new StringBuffer(string);//String变为StringBuffer
         String s = replaceSpace(buffer);
         System.out.println(s);
     }
 //输入：We Are Happy
 //输出：We%20Are%20Happy