/* harjoitus 6 - tehtävä 3 */

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

void prn_message();
void prn_header();
void prn_data();

main()
{
  prn_message();
  prn_header();
  prn_data();
}

void prn_message()
{
  printf("Will compute the expressions given "
	 "in the exercise assignment.\n");
}


void prn_header()
{
  printf("%20s %20s %20s %20s %20s\n",
	 "x", "sin(x)", "x^(-2.5)", "ceil(x)", "ln(x)");
}

void prn_data()
{
  double x;

  /* HUOM: Seuraava silmukka tulostaa vain x:n arvot 2.9:ään asti,
     vaikka selvästi näyttäisi siltä, että tilanne x = 3.0 lasketaan
     myös!! Syy on double (ja float) muuttujien äärellisessä
     tarkkuudessa -- kun tulostaa x:n riittävän suurella tarkkuudella,
     näkee, että sen tarkka arvo on aina hieman suurempi kuin 0.1:n moninkerta:

  for (x = -1.; x <= 3.; x += 0.1) {
    printf("%20.9lf %20.9lf %20.9lf %20.9lf %20.9lf\n",
	   x, sin(x), pow(x, -2.5), ceil(x), log(x));
  }

  /* tilanne on helppo korjata seuraavasti: */
  for (x = -1.; x <= 3. + 0.05; x += 0.1) {
    printf("%20.9lf %20.9lf %20.9lf %20.9lf %20.9lf\n",
	   x, sin(x), pow(x, -2.5), ceil(x), log(x));
  }
}

/* ohjelman tulostus onpi seuraanvanlainen: */
/*
Will compute the expressions given in the exercise assignment.
                   x               sin(x)             x^(-2.5)              ceil(x)                ln(x)
        -1.000000000         -0.841470985                  nan         -1.000000000                 -inf
        -0.900000000         -0.783326910                  nan         -0.000000000                 -inf
        -0.800000000         -0.717356091                  nan         -0.000000000                 -inf
        -0.700000000         -0.644217687                  nan         -0.000000000                 -inf
        -0.600000000         -0.564642473                  nan         -0.000000000                 -inf
        -0.500000000         -0.479425539                  nan         -0.000000000                 -inf
        -0.400000000         -0.389418342                  nan         -0.000000000                 -inf
        -0.300000000         -0.295520207                  nan         -0.000000000                 -inf
        -0.200000000         -0.198669331                  nan         -0.000000000                 -inf
        -0.100000000         -0.099833417                  nan         -0.000000000                 -inf
        -0.000000000         -0.000000000                  nan         -0.000000000                 -inf
         0.100000000          0.099833417        316.227766017          1.000000000         -2.302585093
         0.200000000          0.198669331         55.901699437          1.000000000         -1.609437912
         0.300000000          0.295520207         20.286020648          1.000000000         -1.203972804
         0.400000000          0.389418342          9.882117688          1.000000000         -0.916290732
         0.500000000          0.479425539          5.656854249          1.000000000         -0.693147181
         0.600000000          0.564642473          3.586095691          1.000000000         -0.510825624
         0.700000000          0.644217687          2.439242060          1.000000000         -0.356674944
         0.800000000          0.717356091          1.746928107          1.000000000         -0.223143551
         0.900000000          0.783326910          1.301348831          1.000000000         -0.105360516
         1.000000000          0.841470985          1.000000000          1.000000000         -0.000000000
         1.100000000          0.891207360          0.787985611          2.000000000          0.095310180
         1.200000000          0.932039086          0.633938145          2.000000000          0.182321557
         1.300000000          0.963558185          0.518969242          2.000000000          0.262364264
         1.400000000          0.985449730          0.431201150          2.000000000          0.336472237
         1.500000000          0.997494987          0.362887369          2.000000000          0.405465108
         1.600000000          0.999573603          0.308816178          2.000000000          0.470003629
         1.700000000          0.991664810          0.265385809          2.000000000          0.530628251
         1.800000000          0.973847631          0.230048146          2.000000000          0.587786665
         1.900000000          0.946300088          0.200962950          2.000000000          0.641853886
         2.000000000          0.909297427          0.176776695          3.000000000          0.693147181
         2.100000000          0.863209367          0.156477451          3.000000000          0.741937345
         2.200000000          0.808496404          0.139297492          3.000000000          0.788457360
         2.300000000          0.745705212          0.124646592          3.000000000          0.832909123
         2.400000000          0.675463181          0.112065490          3.000000000          0.875468737
         2.500000000          0.598472144          0.101192885          3.000000000          0.916290732
         2.600000000          0.515501372          0.091741668          3.000000000          0.955511445
         2.700000000          0.427379880          0.083481566          3.000000000          0.993251773
         2.800000000          0.334988150          0.076226314          3.000000000          1.029619417
         2.900000000          0.239249329          0.069824045          3.000000000          1.064710737
         3.000000000          0.141120008          0.064150030          4.000000000          1.098612289
*/

/* huomaa, ettei negatiivisen luvun murtoluku potenssia ole
   määritelty, kuten ei negatiivisen luvun logaritmiakaan (olisi
   oikeastaan imaginaarinen) */