Из одного файла переписать в другой числа,кратные 3

#include<stdio.h>
#include<conio.h>
#include<iostream.h>
#include<stdlib.h>
void main ( )
{ FILE * fp1;
FILE * fp2;
int c,n,i;
clrscr ( );cin>>n;
if ((fp1=fopen("c:\\r\\file1.txt","w+")) == NULL)
{ puts ("don't may open file \n"); return;}
for(i=0;i<n;i++)
{c=random(41)-20;
puts(c,fp1);}
fp2 = fopen("c:\\r\\file2.txt","w+");
while ((c=getc(fp1))!=EOF)
{
if((c%3)==0) putc(c,fp2);}   
fclose(fp1);fclose(fp2);
getch();
}

#include<stdio.h>
#include<conio.h>
#include<iostream.h>
#include<stdlib.h>
void main ( )
{ FILE * fp1,*fp2;
int c,n,i;
clrscr ( );cin>>n;
if ((fp1=fopen("c:\\r\\file1.txt","w+")) == NULL)
{ puts ("don't may open file \n"); return;}
for(i=0;i<n;i++)
{c=random(41)-20;
fprintf(fp1,"%4d",c);}
fp2=fopen("c:\\r\\file2.txt","w");
while ((c=getc(fp1))!=EOF)
{
if((c%3)==0) fprintf(fp2,"%4d",c);}
fclose(fp1);fclose(fp2);
getch();
}