Does break not work on loops anymore?

[Eman]

Hi,
I was trying to solve a Project Euler question. find the largest palindrome from the product of two 3 digit number.

the idea was if i start from the largest i and j, and if it was a palindrome it would be the largest. And I would break from the loop. But it wouldn't work...

I had to use a boolean...so the question is? Does break not work ? It was in an if statement, but since the if was in a loop. It should still break?

I'm baffled here.
Is it ok if I post the code?

[tabstop]

Sure you can post the code. (Obviously the broken code.)

[Salem]

You would need to post a specific example.

break only works for one level, so if you've got some nested loop or something, it will only break one level.

[Eman]

break only works for one level, so if you've got some nested loop or something, it will only break one level.

Oh yes, that's why...
if i used a function, would it break from the function or still that one level?

[Eman]

#include <iostream>
using namespace std; 
int convertToString(long int n) ;
int checkPalindrome(string s);
void main()
{
    int i; 
    int j,large =0 ;
    int num1=0, num2=0 ;
    for(i=999;i>99;i--)
    {
        for(j=999;j>99;j--)
        {
            
           if(!convertToString(i*j))
           {
             
                num1 = i ; 
                num2 =j ; 
                large = i* j ;
                break; 
           }
        }
       
    }
        
        
   cout << num1 << " " << num2 << " " << large  ;

}
int convertToString(long int n) 
{
    
   char d; 
    string s;
    
    while(n>0)
    {
        d =  ((n % 10) + 48) ;
        s = s + d ;
       
        n/=10 ;
    }
 

    return checkPalindrome(s) ;
}
int checkPalindrome(string s)
{
    int l = s.length()-1 ;

    int j = l ;
    
    for(int i=0;i< j;i++)
    {
        if(s[i]!=s[j])
        {   
           return 1;
        }
        j-- ;

    }
    
        return 0 ;
}

[itsme86]

You'll need to add a bool keep_going or something that each loop level checks. Or in this case, a <whisper>goto</whisper> might be prudent.

[hk_mp5kpdw]

for(i=999;i>99;i--)
{
    for(j=999;j>99;j--)
    {
            
       if(!convertToString(i*j))
       {
           
            num1 = i ; 
            num2 =j ; 
            large = i* j ;
            break; 
       }
    }
     
}

Haven't looked at anything other than the break issue, but if you wish to break from both those loops you could probably either:

1. Set i to anything 99 or less immediately prior to calling break
2. Set i and j both to something 99 or less at the end of the if block and not call break at all

[Eman]

It seems to work with the boolean. I will try hk_mp5 suggestion.
Is there anyway to optimize it further? like if i use register int or something.

#include <iostream>
using namespace std; 
int convertToString(long int n) ;
int checkPalindrome(string s);
void main()
{
    int i = 999; 
    int j=999,large =0 ;
    int num1=0, num2=0 ;
 
    while(i>99)
    {
        while(j>i)
        {
          
           if(!convertToString(i*j))
           {
                num1 = i ; 
                num2 =j ; 
              
                large = i* j ; 
                
           }
            if(large>i*j)
                break ; 
          
            j--;
        }  
        j= 999;
        i--;
        
    }
    
   cout << num1 << " " << num2 << " " << large  ;

}
int convertToString(long int n) 
{
    
   char d; 
    string s;
    
    while(n>0)
    {
        d =  ((n % 10) + 48) ;
        s = s + d ;
       
        n/=10 ;
    }
 

    return checkPalindrome(s) ;
}
int checkPalindrome(string s)
{
    int l = s.length()-1 ;

    int j = l ;
    
    for(int i=0;i< j;i++)
    {
        if(s[i]!=s[j])
        {   
           return 1;
        }
        j-- ;

    }
    
        return 0 ;
}