c언어 오류ㅠ returned 1 exit status

#include <stdio.h>

int   aet_gcd (int u, int v)
{
int t;

while (u)
{
  if(u < v)
  {
  t = u ; u = v; v = t;
  }
  u = u - v;
}
return v;
}

void main(void)
{
int u,v;

puts("\n EUCLID1 : Get GCD of two positive integer"
  "\n     Input 0 to end program");

while (1)
  {
  puts("\n\n Iput two positive integer ->");
  scanf("%d %d", &u, &v);
  if (u < 0 || v < 0)
   continue;
  if(u == 0 || v == 0)
   break;
  printf("\n GOD of %d and %d is %d.", u, v, get_gcd(u,v));