cela-cast.c

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#include <stdio.h>
#include <stdlib.h>

#include <math.h>
#include <limits.h>

int main(void) {

  double dabl;
  long   l;//na 64bit long nepretece
//take lze long 'zkratit' na 32bit pomoci CPFLAGS = -m32
//ale nutny package glibc-devel.i686 (Fedora 18)
//int    l;

  printf("LONG_MAX=%li\n", LONG_MAX);
  printf(" INT_MAX=%li\n",  INT_MAX);

  printf("Zadejte cislo: "); fflush(stdout);
  if (1 != scanf("%lf", &dabl)) {
     //nebo lze pouzit isnan()?
     fprintf(stderr, "isnan(dabl): %d, spatny fstup, zadej desetinne cislo!\n", isnan(dabl));
     return EXIT_FAILURE;
  }
//Hmm, bude stacit long na velka double cisla?
//nebude!!! je treba kontrola pomoci <limits.h>
  printf("Cela cast cisla: %g je %li (pomoci (long)typecast)\n", dabl, (long)dabl);
  printf("Cela cast cisla: %g je %li (pomoci long prirazeni)\n", dabl, l=dabl);
  printf("Cela cast cisla: %33.3f je %33.3f (pomoci floor math.h)\n",  dabl, floor(dabl));

  return EXIT_SUCCESS;
}