Largest Palindrome of two digit numbers

Question

The program below is to find palindromes in products of 2 digit numbers (up to 10*11 for trails).

#include<iostream>
using namespace std;
int res1=0
void palindrome(int mul)
{
    int k,res=0,count=0;
    int p=mul;
    while(mul!=0)
    {
        k=mul%10;
        res=(res*10)+k;
        mul=mul/10;
    }
    if(res==p)
              cout<<res<<"is a palindrome:\n"
        {
        if(res1<res) 
            res1=res;
        }
    }

int main()
{
    int mul,j;
    for(int i=1;i<11;i++)
    {
        for(j=1;j<12;j++)
        {

            mul=i*j;
            if(mul>10)
            palindrome(mul);
        }
        cout<<"\n";
    }

    return 0;
}

The above code works for all that I need except for the largest palindrome.

My algorithm is like

Take the product of each combination
Use a function to check whether the result is palindrome if multiplication res is >10 and print the palindrome.
Check for the largest number by comparing with the previous number.

So I have stored the previous value in res1 variable, and I am comparing the res and res1 variables.

According to my logic it checks lastly (88<99) that is true. Now the problem is how to print the last value stored in res variable?

So, your question is _how to output the value of a variable_?? — Vlad, Sep 21 '11 at 11:33
So, you already managed to write code to output a variable, yet you ask how to output another variable? try transferring the knowledge from one to the other variable...? — PlasmaHH, Sep 21 '11 at 11:37
you said **product of 2 digit numbers**, but you are multiplying single digit numbers?? — vivek, Sep 21 '11 at 11:47

Bob2Chiv · Answer 1 · 2011-09-21T11:52:03.150

1

Since you have the Global variable res1 that stores the value of the palindrome, consider adding a cout to output this value: cout<<"Last value: "<<res1<<endl; before you return 0.

Of course, I'd reccommend that your palindrome function instead accept and return res1 to avoid having the global variable and some other semantic type things... but those are different issues which may not matter to you.

edited Sep 21 '11 at 11:52

answered Sep 21 '11 at 11:44

Bob2Chiv

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@MatteoItalia My 'favorite' anti-virus software confused my spelling. Thanks – Bob2Chiv Sep 21 '11 at 11:53
Thank u very much yar. i got it. superb really – srija Sep 21 '11 at 11:56
1

@bhanu If this helped you, I'd appreciate it if you marked the answer as useful or even marked it as the correct answer. Thanks! – Bob2Chiv Sep 21 '11 at 12:11

score 0 · Answer 2 · edited Dec 05 '12 at 02:29

I have written a code to check whether the input number by user is palindrome or not. The code also returns the reverse of given number. Code is as follows:

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

class palindrome
{
    int a;
    int f;
    int b;
    int l;
    int c;
    int count;
public:
    void getdata();
    void counting();
    void reverse();
    void display();
};

void palindrome::getdata()
{
    cout<<"Enter any number having atleast 2 digits";
    cin>>a;
    b=a;
    c=a;
}

void palindrome::counting()
{
    int count=1;
    f=1;
    do
    {
        a=a/10;
        count++;
    }while(a/10!=0);

    for(int k=1;k<count;k++)
    {
        f=f*10;
    }
}

void palindrome::reverse()
{
    l=0;
    for(int i=1;i<=count;i++)
    {
        int k=b%10;
        k=k*f;
        f=f/10;
        l=l+k;
        b=b/10;
    }
    cout<<"\nThe reverse of the number is"<<l;

}

void palindrome::display()
{
    if(l==c)
    {
        cout<<"\nThe number is palindrome";
    }
    else
        cout<<"\nThe number is not palindrome";
}

void main()
{
    palindrome a; 
    clrscr();
    a.getdata();
    a.counting();
    a.reverse();
    a.display();
    getch();
}

Largest Palindrome of two digit numbers

2 Answers2