I wrote a code below and compiled it by gcc4.1.2 with -lm option and checked getting right answer in sample case.
But when I submit it with selecting GCC, then got a compile error.
I cannot understand what error message means(what is `Main.c'?) 
so I tried sometime and got same result, compile error. 
what's happen? did I take a mistake?

#include<stdio.h>
#include<math.h>

#define DEBUG(x)

double hdivpi = 100.0/M_PI;

int f(double x, double y)
{
  double d = sqrt(x*x + y*y);
  double dn = sqrt(hdivpi);
  double tmp;
  double acc =dn;
  int year;

  DEBUG( printf("distance = %lf\n", d); )

  for (year = 1; acc < d; year++){
    DEBUG( printf("acc = %lf;  dn = %lf;  \n", acc, dn); )
    tmp = sqrt(hdivpi +dn*dn);
    acc += tmp- dn;
    dn = tmp;
  }
  return year;
}

int main()
{
  int i, n;
  double x, y;
  
  scanf("%d", &n);
  for (i = 1; i <= n; i++){
    scanf("%lf%lf", &x, &y);
    printf("Property %d: This property will begin eroding in year %d.\n",
	   i, f(x, y));
  }
  printf("END OF OUTPUT.\n");
  return 0;
}



here is error message.

Main.c:6: error: `M_PI' undeclared here (not in a function)
Main.c: In function `f':
Main.c:10: error: syntax error before '/' token
Main.c:13: error: `dn' undeclared (first use in this function)
Main.c:13: error: (Each undeclared identifier is reported only once
Main.c:13: error: for each function it appears in.)
Main.c:20: error: `tmp' undeclared (first use in this function)

• Re:compile error problem 1005 (1641) frkstyc 2008-05-19 21:03:30
  • Re:compile error problem 1005 (193) yatt 2008-05-19 21:38:31
    • Re:compile error problem 1005 (203) frkstyc 2008-05-19 22:21:47
      • Re:compile error problem 1005 (93) yatt 2008-05-20 11:18:29