#include <stdio.h>

int main ()
{
  int i = 5;
  long j = 6;
  double d = 3.141;

  j = i;         // Works fine. Implicit cast from int to long.
  d = i;         // Works fine. Implicit cast from int to double

  i = j;         // Does not compile.
  i = d;         // Does not compile.

  d = 3.141;
  i = (int) j;   // Compiles. Explicit cast from long to int.
  i = (int) d;   // Compiles. Explicit cast from double to int.

  // Cast's can be used in any expression:
  printf ("The int part of d=%lf is %d\n", d, (int) d);
}