Palindromes

[elsa]

hi everybody..i need to define two functions that test for word Palindromes..

1- void bool isPalindromeUsi ngIteration(str ing ) that takes a string as a paremeter and tests if it is a Palindrome using a loop structure.

2- bool isPalindromeUsi ng Recursion(strin g) that takes a string as paremeter and tests if it is a Palindrome using a recursion.

i need to explore the standard c++ library string and cctype to be able to define these two functions..
i want to use arrays in the progarm.. can u please help me..

[Ganon11]

What ideas do you have? What code have you got so far?

A good start would be to figure out how you'll test for a palindrome. To understand this, you'll need to know what a palindrome is - understanding its nature will help your test.

[elsa]

i know what palindromes are..and i know i that i have to use the for loop and try to find out if the firt letter is the same as the last letter..but how can i start and how can i use the arrays to do that? plz help me

[Ganon11]

Well, if you are using strings, you can treat them as an array of characters. Thus, you can use the brackets [] to get a character at a certain position and compare it to the last character, etc.

How will you check using recursion?

[elsa]

i dont really know what recursion means..this thing is a part of an assignment that is due on the 21st of january..the first part of the assignment is to build a program that will convert a decimal number into a binary number using arthmetic operators and bitwise operators..i did the first part as this:
#include<iostre am>
#include<string >
using std::string;
using std::cout;
using std::cin;
using std::endl;

// Here are some function declarations

unsigned short getMenuSelectio n( );
void binaryConversio nUsingArithmeti cOperators(unsi gned long);
void binaryConversio nUsingBitwiseOp erators (unsigned long);

// Utilityfunction s
void initializeArray (unsigned short[],int) ;

void printBinary(uns igned short[ ],int) ;


int main()
{
unsigned short choice;
do
{
choice = getMenuSelectio n();

cout <<"You chose Menu Option #"<<choice<<end l ;
switch(choice)
{
case 1 :
unsigned long a;
cout<<" Please enter an integer " ;
cin>>a ;
binaryConversio nUsingArithmeti cOperators(a);
break ;
case 2 :
cout<<" Please enter an integer " ;
cin >>a ;
binaryConversio nUsingBitwiseOp erators(a) ;
break ;
case 3 :
cout<<"Please enter a string ";
break;
case 4:
cout<<"Please enter a string ";
break;
case 5:
break;
default:
cout<<"you should never get here\a\a\a\a!!! ";
}
}while(choice != 5);
cout<<"you choose to quit\a\a\a"<<en dl;
return 0;
}
unsigned short getMenuSelectio n()
{
unsigned short selection=0;
do
{
cout<<"-1- Binary Conversion using Arithmetic Operators"<<end l;
cout<<"-2- Binary Conversion using Bitwise Operators"<<end l;
cout<<"-3- Testing for Palindroms Using Iteration"<<end l;
cout<<"-4- Testing for Palindroms Using Recursion"<<end l;
cout<<"-5- Quit"<<endl;
cout<<"please enter your selection <1-5>:"<<endl;
cin>>selection;
}
while(selection <1 || selection>5);
return selection;
}
void binaryConversio nUsingArthemati cOperators(unsi gned long x)
{
unsigned short binaryDigit[100], numberOfDigits= 0;
initializeArray (binaryDigit,10 0);
do
{
binaryDigit[numberOfDigits+ +]=x%2;
x=x/2;
}while(x!=0);
printBinary(bin aryDigit,number OfDigits);
}

void binaryConversio nUsingBitwiseOp erator(unsigned long x)
{
unsigned short binaryDigit [100],
numberOfDigits= 0;
initializeArray (binaryDigit , 100);
do
{
binaryDigit[numberOfDigits+ +]=x&1;
x=x>>1;
}while(x!=0);
printBinary(bin aryDigit, numberOfDigits) ;
}

void initializeArray (unsigned short a[], int size)
{
for(int i=0;i<size; i++)
a[i]=0;
}

void printBinary(uns igned short a[], int size)
{
for(int i=size-1; i>=0; i--)
cout<<a[i];
cout<<endl;
}
but the second part was hard..and i left things unwritten..and i really need the help..