The checksum & palindrome algorithm

With a restaurant checksum for my tip calculator, the sum of the dollar digits is equal to the cents. Here’s my checksum code:

   1: int nAddUpLeftDecimals(int nX)

   2:     {

   3:         int remain, sum=0;

   4:         nX = nX/100;

   5:         while(nX >= 1)

   6:         {

   7:             remain = nX%10;

   8:             sum = sum + remain;

   9:             nX=nX/10;

  10:         }

  11:

  12:         return sum ;

  13:     }

  14:

  15:

  16: int Checksum(int nX) {

  17:

  18:         while(nAddUpLeftDecimals(nX) != nX%100 ) {

  19:             nX += 1;

  20:         }

  21:         return nX;

  22:     }

and my palindrome code:

   1: boolean nCheckPalindrome(int nX) {

   2:

   3:     int yy,xx,zz=0;

   4:     yy = nX;

   5:     while(nX>0)

   6:     {

   7:       xx=nX%10;

   8:       nX/=10;

   9:       zz=zz*10 + xx;

  10:      }

  11:

  12:     if (zz==yy)

  13:      return  true;

  14:    else

  15:      return  false;

  16:

  17: }

  18:

  19: int Palindrome(int nX) {

  20:     while(!nCheckPalindrome(nX)) {

  21:         nX += 1;

  22:     }

  23:     return nX;

  24: }