Inverse of a string

JDK's approach:

1 String str =2new StringBuilder (str). reverse (). toString ();

Achieve yourself:

1  Public classstringdemo{2      Public Static voidMain (string[] args) {3System.out.println (Reverse ("Hello world!"));//!dlrow Olleh4     }5      Public Staticstring Reverse (String str) {6        Char[] Arrs =Str.tochararray ();7         Chartemp = ';8          for(inti = 0, j = arrs.length-1; I < J; i++,j--){9temp =Arrs[i];TenArrs[i] =Arrs[j]; OneARRS[J] =temp; A         } -StringBuilder SB =NewStringBuilder (); -          for(CharS:arrs) { the Sb.append (s); -         } -         returnsb.tostring (); -     } + } -  +  Public voidReverse2 (FinalString str) { A    Char[] chars =Str.tochararray (); atStringBuilder SB =NewStringBuilder (); -     for(inti = chars.length-1;i>0; i--){ -Sb.append (Char[i]); -    } -    returnsb.tostring (); -}

* "I love China", reverse the character and turn it into "China love I"
Method One: one character for one character change

1  Public classStringreverse {2     3      Public voidSwapChar[] arr,intBeginintend) {4          while(Begin <end) {5             Chartemp =Arr[begin];6Arr[begin] =Arr[end];7Arr[end] =temp;8begin++;9end--;Ten         } One     } A      Publicstring Swapwords (String str) { -         Char[] arr =Str.tochararray (); -Swap (arr, 0, Arr.length-1); the         intBegin = 0; -          for(inti = 1; i < arr.length; i++) { -             if(Arr[i] = = ") { -Swap (arr, begin, I-1); +begin = i + 1; -             } +         } A  at         return NewString (arr); -     } -      Public Static voidMain (string[] args) { -String str = "I love java"; -System.out.println (Newstringreverse (). Swapwords (str)); -     } in}

Method Two: (using the method provided by the JDK)

1  Public classMain {2      Public Static voidMain (string[] args) {3Scanner sc =NewScanner (system.in);4String str =sc.nextline ();5string[] SArr = Str.split ("");//I Love Java6list<string> list =arrays.aslist (SARR);7 collections.reverse (list);8          for(String word:list) {9System.out.print (word+ "");Ten         } One     } A}

Method 3: Change a word by one word

1  Public classstringdemo{2      Public Static voidMain (string[] args) {3System.out.println (Reverse ("Hello world!"));//world! Hello4     }5      Public Staticstring Reverse (String str) {6String [] Arrs = Str.split ("");7String temp = "";8          for(inti = 0, j = arrs.length-1; I < J; i++, j--){9temp =Arrs[i];TenArrs[i] =Arrs[j]; OneARRS[J] =temp; A         } -StringBuilder SB =NewStringBuilder (); -          for(String s:arrs) { theSb.append (s). Append (""); -         } -       returnsb.tostring (); -     } +}

Inverse of a string