i have c++ book...and there is a question about checking if the strng is palindrome or not.....before i look into the solution at the last page of the book...i have tried alot to do it myself..but unfrtunately i couldnt do it........so..i pened the solution page and here is the solution of the book :

# include <iostream.h>
# include <conio.h>

int main()

{
    char text[80];
    int beg;;
    int back;
    int flag;
    int l;

    cout<<"Enter the string:"<<endl;
    cin>>text;

    l=0;


    while(text[l] != '\0')
        l++;
        flag=1;
        beg=0;
        back=l-1;

    while( (beg<=back) && flag )
    {
        if(text[beg] == text[back])
            flag=1;
        else
            flag=0;
        beg++;
        back--;
    }

    if(flag)

    cout<<"Yes its a palindrome"<<endl;
    else
        cout<<"No its not a palindrome"<<endl;
}


what i dont understand is the logic of this program really..!

int beg ...> is the beginig of the text
int back...> the end of the text....

why they are declared as integers?

int flag....> what is flag?
i didnt understand this word


thank you very much

Hi ahmed,
I try to explain it for you with help of a simple example,
suppose you enter your name,"ahmed"
so it stores in an array of chars
text[0]=a,text[1]=h,text[2]=m,text[3]=e,text[4]=d,text[5]='\0'
as you see in C++ the end of a string is defined as a '\0' character.
integer variable beg shows the beginning of the text(0),
integer variable back shows the end of the text(4),
integer variable l shows the length of the text(5),
now the algorithm starts to traverse from the beginning and the end of the text equally
beg++ back--
----> <----
    a h m e d
in every loop beg increases one unit and back decreases one unit for checking the letters have the same distances from beginning and the end of the text.if there are two different letters the flag becomes 0 and your program exits from the loop cycle and tells you the text wasnt palindrome otherwise the flags remains 1 and the Conditional statement tell you the text was palindrome.
HtH.

--------------------------------------------
Mehdi.:)

than you very much mehdi.....you explained it nicely.:)