int fun1 ( int a, int b );  //遵循1
int fun2 ( int a, int b );  //遵循2

int main ( void )
{
  int a, b, c, d;

  a = 10;
  b = 5;
  c = fun1 ( a, b );
  d = fun2 ( a, b );

  return ( 0 );
}

int fun1 ( int a, int b )
{
  int ret;

  ret = a + b;

  return ret;
}

int fun2 ( int a, int b )
{
  int ret;

  ret = a - b;
  
  return ret;
}