字符串——将字符串间的单词做逆序调整

思路：

public class ReverseSentence {

	public static void main(String[] args) {
		// TODO Auto-generated method stub
		System.out.println(reverseSentence("I'm a student"));
		System.out.println(reverseSentence("I'm a student").length());
		
		System.out.println(reverseSentence("  I'm a student"));
		System.out.println(reverseSentence("  I'm a student").length());
		
		System.out.println(reverseSentence("I'm a student  "));
	}
	
	//先翻转整个句子，再翻转每个单词
	public static String reverseSentence(String str){
		
		if(str==null||str.length()==0)
			return null;
		
		char ch[]=str.toCharArray();
		f(ch,0,ch.length-1);
		int begin=0;
		int end=0;
		while(end0;i--){
	            sb.append(s[i]);
	            sb.append(" ");
	        }
	        sb.append(s[0]);
	        return sb.toString();
	    }

}