Use the "back-to-text algorithm" to review the C ++ language ., Text Algorithm

Use the "back-to-text algorithm" to review the C ++ language ., Text Algorithm

1. What is text return?

Given a string, read from the back and from the back without changing the string sequence. For example, the customer service phone number of Hebei rural credit cooperatives is "96369". Whether it is read from the back to the back or back to the back, the positions of each character remain unchanged.

Ii. function implementation

(1) give a string and determine whether it is a return text.

(2) given an arbitrary string, determine whether it can be converted back to text. If it can be converted back to text, a specific algorithm is provided.

III. C ++ language implementation version (subsequent implementation of the JAVA language version)

(1) header file (BackText. h)

/*
* BackText. h
*
* Created on: July 15, September 30, 2016
* Author: gaodianhua
*/
# Include <string>
# Include <cstring>
# Include <map>
# Ifndef BACKTEXT_H _
# Define BACKTEXT_H _
Using namespace std;

Class BackText {
String text;
Map <char, int> mapBychar;
Int checksum;
Public:
BackText ();
BackText (char str []);
BackText (string text );
Virtual ~ BackText ();
Bool isBackText ();
Void print () const;
Void countDiffCh ();
Void convert (char * dest );

};

# Endif/* BACKTEXT_H _*/

(2) Implementation of Classes

/*
* BackText. cpp
*
* Created on: July 15, September 30, 2016
* Author: gaodianhua
*/

# Include "BackText. h"
# Include <iostream>
# Include <string>
# Include <iterator>
# Include <cstring>
# Include <cstdlib>
# Include <map>

Using namespace std;

BackText: BackText (){
}

BackText ::~ BackText (){
This-> checksum = 0;
}

BackText: BackText (char * str ){
This-> text = str;
This-> checksum = 0;
}

BackText: BackText (string str ){
This-> text = str;
This-> checksum = 0;
}

Bool BackText: isBackText (){
String: iterator it1, it2;
It1 = text. begin ();

It2 = text. end ()-1;
For (; it1 <= it2; it1 ++, it2 --){
If (* it1! = * It2)
Return false;
}
Return true;
}

Void BackText: print () const {
Cout <this-> text <endl;
}

Void BackText: countDiffCh (){
String: iterator it1, it2;
String temp;
Temp. clear ();
Int index = 0;
For (it1 = text. begin (); it1 <text. end (); it1 ++ ){
If (strchr (temp. data (), * it1) = NULL ){
Temp. insert (index, 1, * it1 );
Index ++;
}
}
For (it2 = temp. begin (); it2 <temp. end (); it2 ++ ){
Int count = 0;
For (it1 = text. begin (); it1 <text. end (); it1 ++ ){
If (* it1 = * it2 ){
Count ++;
Checksum ++;
}
}
MapBychar. insert (pair <char, int> (* it2, count ));
}

Map <char, int >:: iterator m;
For (m = mapBychar. begin (); m! = MapBychar. end (); m ++)
Cout <m-> first <"" <m-> second <endl;
}

Void BackText: convert (char * dest ){
If (isBackText ()){
Strcpy (dest, text. data ());
Return;
}
Int cnt = 0;
Map <char, int >:: iterator m;
For (m = mapBychar. begin (); m! = MapBychar. end (); m ++ ){
If (m-> second % 2! = 0 ){
Cnt ++;
}
}
If (cnt> 1 ){
Cout <"this string cannot be converted into a back-to-text" <endl;
Return;
}
Cout <"Start conversion..." <endl;
Int begIndex = 0;
Int endIndex = checksum-1;
Bool oddflag = 0;
Char oddchar;
For (m = mapBychar. begin (); m! = MapBychar. end (); m ++ ){
If (checksum % 2 = 0 ){
For (int I = 0; I <m-> second/2; I ++ ){
Dest [begIndex ++] = m-> first;
Dest [endIndex --] = m-> first;
}
} Else {
If (m-> second % 2 = 0 ){
For (int I = 0; I <m-> second/2; I ++ ){
Dest [begIndex ++] = m-> first;
Dest [endIndex --] = m-> first;
}
} Else {
Oddchar = m-> first;
Oddflag = true;
Continue;
}
}
}
If (oddflag ){
Map <char, int >:: iterator it;
It = mapBychar. find (oddchar );
If (it = mapBychar. end ()){
Cout <"do not find" <oddchar <endl;
Return;
}
For (int I = 0; I <it-> second; I ++ ){
Dest [begIndex ++] = it-> first;
}
}
}

(3) main Function

/*
* Main. cpp
*
* Created on: July 15, September 30, 2016
* Author: gaodianhua
*/
# Include <iostream>
# Include "BackText. h"
# Include <cstdlib>
# Include <string>
Using namespace std;
Int main (){
String text;
Text. clear ();
Cout <"enter a string :";
Cin> text;
BackText bt = BackText (text );
Bt. print ();
If (! Bt. isBackText ())
Cout <"not a return string" <endl;
Bt. countDiffCh ();
Char dest [100];
Memset (dest, 0x0, sizeof (dest ));
Bt. convert (dest );
Cout <dest <endl;
Return 0;
}