算法——小练习

 1 public String forReverse(String original) {
 2         char[] temp = original.toCharArray();
 3         StringBuffer sb = new StringBuffer();
 4         int tempLenth = temp.length;
 5         for (int i = tempLenth - 1; i >= 0; i--) {
 6             sb.append(temp[i]);
 7         }
 8         return sb.toString();
 9 
10     }

 1         String input = "Hello world"; 
 2         char[] temparray = input.toCharArray(); 
 3         int left, right=0; 
 4         right = temparray.length-1; 
 5   
 6         for (left=0; left < right ; left++ ,right--) 
 7         { 
 8             // Swap values of left and right 
 9             char temp = temparray[left]; 
10             temparray[left] = temparray[right]; 
11             temparray[right]=temp; 
12         } 
13   
14         for (char c : temparray) 
15             System.out.print(c); 

 1 public String forReverse2(String original) {
 2         char[] value = original.toCharArray();
 3         int count = value.length;
 4         int n = count - 1;
 5         for (int j = (n - 1) >> 1; j >= 0; j--) {
 6             int k = n - j;
 7             char cj = value[j];
 8             char ck = value[k];
 9             value[j] = ck;
10             value[k] = cj;
11 
12         }
13         return String.copyValueOf(value);
14     }