如何使用數組刪除特定字符的迴文？

Question

我的程序應該測試迴文，然後將其反向打印出來，但沒有像'！'，'或'？'這樣的字符。因此，輸入的「夫人我是亞當」輸入「madamimadam」，沒有大寫字母，空格或標點符號。我能夠編寫這個程序，但你怎麼做另一部分去除這些字符/大寫？同樣對於我的數組，當程序運行時，它會在打印輸出時在迴文和迴文之間輸出一組奇數字符。我相信這是因爲數組正在填充額外的字符空間，所以我如何解決這個問題呢？

#include<iostream> 
#include<string> 
using namespace std; 

int main() 
{ 
    //Variables and arrays 
    int const index = 30; 
    char Phrase[index]; 
    char Reverse[index]; 
    char* Palindrome = Reverse; 
    int i, j; 

    cout << "Please enter a sentence to be tested as a palindrome: "; 
    cin.getline(Phrase, 30); 
    int length = strlen(Phrase); 

    bool test = true; 

    for(i = 0; i != length/2; i++) //Loops from zero to half of the string 
    { 
     if(test) // if it is a palindrome so far 
     { 
      if(Phrase[i] != Phrase[length-i-1]) //To check if the characters match 
      { 
       test = false; 
      } 

     } 
     else 
     { 
      break; 
     } 
    } 

    if(test) 
    { 
     cout << endl << "Phrase/Word is a Palindrome." << endl << endl; 
     for(j = strlen(Phrase) - 1; j >= 0; Palindrome++, j--) 
     { 
      *Palindrome = Phrase[j]; 
     } 
     cout << "The phrase and reverse statement is: " << Reverse << endl << endl; 
    } 
    else 
    { 
     cout << endl << "Phrase/Word is not a Palindrome." << endl << endl; 
    } 

    system("Pause"); 
    return 0; 
} 

Answer 1

#include <iostream> 
#include <string> 
#include <cctype> 
    using namespace std; 

int main() 
{ 
//Variables and arrays 
int const index = 80; 
char Phrase[index]; 
char NewPhrase[index]; 
int i, j, k, l; 
bool test = true; 

//Prompt user for the phrase/word 
cout << "Please enter a sentence to be tested as a palindrome: "; 
cin.getline(Phrase, 80); 

//Make everything lowercase, delete spaces, and copy that to a new array 'NewPhrase' 
for(k = 0, l = 0; k <= strlen(Phrase); k++) 
{ 
    if((Phrase[k] != ' ') && (ispunct(Phrase[k]) == false)) 
    { 
     NewPhrase[l] = tolower(Phrase[k]); 
     l++; 
    } 
} 

int length = strlen(NewPhrase); //Get the length of the phrase 

for(i = 0, j = length-1; i < j; i++, j--) 
{ 
    if(test) //Test to see if the phrase is a palindrome 
    { 
     if(NewPhrase[i] != NewPhrase[j]) 
      test = false; 
    } 
    else 
     break; 
} 

if(test) 
{ 
    cout << endl << "Phrase/Word is a Palindrome." << endl << endl; 
    cout << "The Palindrome is: " << NewPhrase << endl << endl; 
} 
else 
    cout << endl << "Phrase/Word is not a Palindrome." << endl << endl; 

system("Pause"); 
return 0; 
} 

Answer 2

你忘了終止\0添加到Reverse。循環後添加*Palindrome = '\0'。

Answer 3

只使用單獨的迭代器。取而代之的

for(i = 0; i != length/2; i++) 

做

for(i = 0, j = length-1; i < j; i++, j--) 

然後你if語句，你可以這樣做

if(test) // if it is a palindrome so far 
{ 
    while(!isalpha(Phrase[i]) && i < j) { i++; } 
    while(!isalpha(Phrase[j]) && i < j) { j--; } 
    if(Phrase[i] != Phrase[j]) //To check if the characters match 
    { 
     test = false; 
    } 

，這將導致你的程序忽略除ISN任何字符不是信。如果你想讓它識別數字，你也可以使用isalphanum。