something wrong with this?

[Unregistered]

hi, I have a problem with my program. what the program does is prints a number backwards. however, the function fails for certain numbers. why is this?

I am currently using MSVC++ 6.0

#ifndef _INC_IOSTREAM
#include <iostream.h>
#endif

long int newvalue = 0; //variable to store the number backwards

void PrintNumberBackwars(long int x) //recursive function
{
long int temp = x / 10;
temp = x - temp * 10;
newvalue = newvalue * 10 + temp;
cout << temp;
x /= 10;
if ( x != 0 ) PrintNumberBackwards(x);
else cout << endl;
}

int main(void) // main driver function
{
long int x;
cin >> x;
if ( cin.fail() ) return 0;
PrintNumberBackwards(x);
cout << newvalue;
return 0;
}

[Unregistered]

also, which variables (if any) can I change to type reference (&) ?

[Sorensen]

>the function fails for certain numbers.

What numbers does it fail for?

>which variables (if any) can I change to type reference (&) ?

You could put newvalue in main() and pass it by reference into PrintNumberBackwards(), recursively passing by reference each time.

[Unregistered]

ok, so is it better to leave the global variable alone or is it better to make it a local and pass it by reference? which one saves more memory?

also, numbers such as 202020202020 and other big numbers don't work. why don't they? I tested the program manually by paper and everything works well. the output from my example turns out to be something like 7463847412 on output and the variable has a value of -1126087180. is it the program or is there something wrong with my algorithm?

thanks in advance.

[Unregistered]

try using a long double for all your long ints. That will make more space for your numbers. If the algorithom works right, it should clear up the problem.

[golfinguy4]

Do you have to use ints, doubles, ect? It would be a lot easier if u could just have the input be a character array. From there, you could have the function reverse the numbers in a different array by finding how long the array is.