c++ palindrome problem

[nonsatisscire]

thanks

[Dukaim]

A do/while(word != end)?

[nonsatisscire]

ok, the do/while caused it to loop, but the end statement is not terminating the program. Another problem I have is that the palindromes should not be case sensitive..

Thanks for the help by the way.

[nonsatisscire]

#include <iostream>
#include <fstream>
#include <cstring>


using namespace std;

int main(void){
char word[81];
do{
bool palindrome=true;




cout << "Please enter a word" << endl;
cin>>word;
int length = strlen(word);
int(length/2);
if (length>0){
for(int i=0;i<(length);i++)
{
if(word[i]!=word[length-1-i])
palindrome=false;
}
}
if(palindrome==true)
{
cout << "The word is a palindrome" << endl;
}
else
{
cout << "The word is not a palindrome" << endl;
}

}while (word != "END");

return(0) ;

}

[nathan10]

As I understand your code and the problem you are trying to solve, it seems that your test for a palindrome is incorrect. Dividing by 2 means you will miss odd lettered palindromes like 'level'. You use the code word[i] when I believe you mean to use the code word.length[i]. The latter examines each individual letter of the string in word. The former does not.

[sohguanh]

I don't know if a single character is considered a palindrome or not.

string word;
do{
bool palindrome=true;

cout << "Please enter a word" << endl;
cin >> word;
int cnt = word.length()/2;
int wordLen = word.length()-1;
for(int i=0; i<cnt; i++, wordLen--) {
  if (word[i] != word[wordLen]) {
    palindrome = false;
    break;
  }
}
palindrome ? cout << "The word is a palindrome\n" : cout << "The word is not a palindrome\n";

}while (word != "END");

[Fresh Grass]

How about you just create an infinite loop, then add this after cin:
if (word == "END") break; // or return 0 if you want to quit right away.

It's bad UI to tell the user that the word (END) isn't a palindrome when the user just want's to quit.

[sohguanh]

Hi Fresh Grass, I am working based on OP original code. I agree UI wise it is not intuitive but hey I am not supposed to write the whole program. I am supposed to help him resolve the critical portion of it. I believe the OP should be able to change the UI itself cuz afterall the detection of palindrome has already been done.

[coder777]

hello nonsatisscire,

taken what sohguanh wrote you can use 'reverse' with strings to easily solve that problem:

do{
cout << "Please enter a word" << endl;
cin >> word;
string w2 = word;
reverse(w2.begin(), w2.end());

(word == w2) ? cout << "The word is a palindrome\n" : cout << "The word is not a palindrome\n";

}while (word != "END");

[nonsatisscire]

Thanks for the help! The program works fine as is, but for some reason it still won't terminate when I enter "END"..

#include <iostream>
#include <fstream>
#include <cstring>


using namespace std;

int main(void){
char word[81];
do{
bool palindrome=true;


cout << "Please enter a word" << endl;
cin>>word;
int length = strlen(word);
for (int i=0; i<length; i++){
word[i] = toupper(word[i]); 
}
int(length/2);
if (length>0){
for(int i=0;i<(length);i++)
{
if(word[i]!=word[length-1-i]) 
palindrome=false;
} 
}
if(palindrome==true)
{ 
cout << "The word is a palindrome" << endl; 
}
else
{
cout << "The word is not a palindrome" << endl; 
}

} while (word!="END");

return(0) ;

}

[coder777]

if you use that char word[81]; this line while (word!="END"); compares 2 pointers which are always different. then you must use (0 == strcmp(word, "END"))

[nonsatisscire]

coder777- this doesn't seem to fix the problem..

[coder777]

well, then use (0 != strcmp(word, "END"))