ld returned 1 exit status

[derrick_chi]

    I am using the g++ compiler to compile the program shown below,
and I am getting this error "ld returned 1 exit status"
can anyone help me with this error.


#include "stdio.h"
#include "iostream."
#include "math.h"




unsigned int GCD_PR(unsigned int REGa, unsigned int REGb);


 main() {

  unsigned int ARRAY[32];
  unsigned int Loop_Control_V, Reg1, Reg2, GCD, new_value;


  for ( int i = 0; i < 31; ++ i ) {


        new_value = i + ( 3 * (4) );

          if ( new_value % 2 != 0 ) {

               new_value = new_value * 4;
               }

          else{
                 new_value = new_value * 10;
                 }

         ARRAY[i] = new_value;
         }

     Loop_Control_V = 0;

          while ( Loop_Control_V < 30 ) {

                if ( ARRAY[Loop_Control_V] > ARRAY[Loop_Control_V +
1] ) {


                     Reg1 = ARRAY[Loop_Control_V];
                     Reg2 = ARRAY[Loop_Control_V + 1];
                     }

                else {
                     Reg1 = ARRAY[Loop_Control_V + 1];
                     Reg2 = ARRAY[Loop_Control_V];
                     }

          GCD = GCD_PR(Reg1,Reg2);
          //cout << " The GCD of "<<Reg1<<" and "<<Reg2<<" is
"<<GCD<<endl;
          Loop_Control_V = Loop_Control_V + 1;

          }

}


unsigned int GCD_PR(unsigned int REGa, unsigned int REGb) {

unsigned int temp1, temp2, GCD;

     temp1 = REGa;
     temp2 = REGb;

     while ( temp1 != temp2 ) {

           if ( temp1 > temp2 ) {

           temp1 = temp1 - temp2;
           }
             else {
                      temp2 = temp2 - temp1;
                      }
             }
     GCD = temp1;
  return GCD;
 }