UVa 449 - Majoring in Scales

Accepted date: 2015-03-11
Ranking (as of 2015-03-11): 14 out of 161
Language: C++

/*
  UVa 449 - Majoring in Scales

  To build using Visual Studio 2012:
    cl -EHsc -O2 UVa_449_Majoring_in_Scales.cpp
*/

#include <cstdio>
#include <cstring>

const int nr_keys = 12, nr_notes = 7, nr_intervals = 7;

const char* major_keys[nr_keys][nr_notes] = {
  {"C", "D",  "E",  "F",  "G",  "A",  "B"},
  {"Db",  "Eb", "F",  "Gb", "Ab", "Bb", "C"},
  {"D", "E",  "F#", "G",  "A",  "B",  "C#"},
  {"Eb",  "F",  "G",  "Ab", "Bb", "C",  "D"},
  {"E", "F#", "G#", "A",  "B",  "C#", "D#"},
  {"F", "G",  "A",  "Bb", "C",  "D",  "E"},
  {"Gb",  "Ab", "Bb",   "Cb", "Db", "Eb", "F"},
  {"G", "A",  "B",  "C",  "D",  "E",  "F#"},
  {"Ab",  "Bb", "C",  "Db", "Eb", "F",  "G"},
  {"A", "B",  "C#", "D",  "E",  "F#", "G#"},
  {"Bb",  "C",  "D",  "Eb", "F",  "G",  "A"},
  {"B", "C#", "D#", "E",  "F#", "G#", "A#"}
};

const char* intervals[nr_intervals] = {
  "OCTAVE", "SECOND", "THIRD", "FOURTH", "FIFTH", "SIXTH", "SEVENTH"
};

int main()
{
  int i, n;
  char scale[4];
  while (scanf("%s", scale) != EOF) {
    const char* (*pkey)[nr_notes];
    for (i = 0; i < nr_keys; i++)
      if (!strcmp(scale, major_keys[i][0])) {
        pkey = &major_keys[i];
        break;
      }
    printf("Key of %s\n", scale);
    char note[4], dir[8], interval[16];
    scanf("%s %s %s", note, dir, interval);
    while (true) {
      char* p = strchr(interval, ';');
      bool next = false;
      if (p) {
        *p = '\0';
        next = true;
      }
      for (n = 0; n < nr_notes; n++)
        if (!strcmp(note, (*pkey)[n]))
          break;
      if (n == nr_notes)
        printf("%s: invalid note for this key\n", note);
      else {
        for (i = 0; i < nr_intervals; i++)
          if (!strcmp(interval, intervals[i]))
            break;
        if (dir[0] == 'U') {
          n += i;
          if (n >= nr_notes)
            n -= nr_notes;
        }
        else {
          n -= i;
          if (n < 0)
            n += nr_notes;
        }
        printf("%s: %s %s > %s\n", note, dir, interval, (*pkey)[n]);
      }
      if (next) {
        strcpy(note, p + 1);
        scanf("%s %s", dir, interval);
      }
      else
        break;
    }
    putchar('\n');
  }
  return 0;
}