First commit

LICENSE.txt

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+Freeware License, some rights reserved
+
+Copyright (c) 2015 Giulio Zambon
+
+Permission is hereby granted, free of charge, to anyone obtaining a copy 
+of this software and associated documentation files (the "Software"), 
+to work with the Software within the limits of freeware distribution and fair use. 
+This includes the rights to use, copy, and modify the Software for personal use. 
+Users are also allowed and encouraged to submit corrections and modifications 
+to the Software for the benefit of other users.
+
+It is not allowed to reuse,  modify, or redistribute the Software for 
+commercial use in any way, or for a user�s educational materials such as books 
+or blog articles without prior permission from the copyright holder. 
+
+The above copyright notice and this permission notice need to be included 
+in all copies or substantial portions of the software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS OR APRESS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
+
+

README.md

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+#Apress Source Code
+
+This repository accompanies [*Sudoku Programming with C*](http://www.apress.com/9781484209967) by Giulio Zambon (Apress, 2015).
+
+![Cover image](9781484209967.jpg)
+
+Download the files as a zip using the green button, or clone the repository to your machine using Git.
+
+##Releases
+
+Release v1.0 corresponds to the code in the published book, without corrections or updates.
+
+##Contributions
+
+See the file Contributing.md for more information on how you can contribute to this repository.

contributing.md

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+# Contributing to Apress Source Code
+
+Copyright for Apress source code belongs to the author(s). However, under fair use you are encouraged to fork and contribute minor corrections and updates for the benefit of the author(s) and other readers.
+
+## How to Contribute
+
+1. Make sure you have a GitHub account.
+2. Fork the repository for the relevant book.
+3. Create a new branch on which to make your change, e.g. 
+`git checkout -b my_code_contribution`
+4. Commit your change. Include a commit message describing the correction. Please note that if your commit message is not clear, the correction will not be accepted.
+5. Submit a pull request.
+
+Thank you for your contribution!

sources/Generator/brute.c

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+/* brute.c
+ *
+ * Copyright (C) 2015  Giulio Zambon  - http://zambon.com.au/
+ *
+ */
+#include <stdio.h>
+#include <stdlib.h>
+#include <time.h>
+#include "brute.h"
+#include "def.h"
+#include "inconsistent_unit.h"
+
+int brute() {
+  int result = BRUTE_SUCCESSFUL;
+  unsigned long start_time = clock()/CLOCKS_PER_SEC;
+  unsigned long this_time;
+  char initial[9][9];
+  for (int k = 0; k < 9; k++) {
+    for (int j = 0; j < 9; j++) {
+      initial[k][j] = grid[k][j];
+      }
+    }
+  int k = 0;
+  int j = 0;
+  do {
+    do {
+      if (initial[k][j] == 0) {
+        int i = grid[k][j] + 1;
+        if (i > 9) {
+          grid[k][j] = 0;
+          do {
+            do { j--; } while (j >= 0 && initial[k][j] != 0);
+            if (j < 0) {
+              k--;
+              if (k < 0) {
+                result = BRUTE_IMPOSSIBLE;
+                goto done;                                                //==>
+                }
+              j = 8;
+              }
+            } while (initial[k][j] != 0);
+          } // if (i..
+        else {
+          grid[k][j] = i;
+          int kB = k/3*3+j/3;
+          if (    !inconsistent_unit("row", k, row[k])
+               && !inconsistent_unit("column", j, col[j])
+               && !inconsistent_unit("box", kB, box[kB])
+               ) {
+            j++;
+            }
+          } // if (i.. else
+        } // if (initial[k][j]..
+      else {
+        j++;
+        }
+      this_time = clock()/CLOCKS_PER_SEC;
+      if (this_time - start_time > BRUTE_MAX_TIME) {
+        result = BRUTE_TIMEOUT;
+        goto done;                                                        //==>
+        }
+      } while (j < 9);
+    k++;
+    j = 0;
+    } while (k < 9);
+
+done:
+  return result;
+  }

sources/Generator/brute.h

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+/* brute.h
+ *
+ * Solves a Sudoku by brute force
+ *
+ * See below for the return codes
+ *
+ * Copyright (C) 2015  Giulio Zambon  - http://zambon.com.au/
+ *
+ */
+#ifndef BRUTE
+#define BRUTE
+
+#define BRUTE_SUCCESSFUL  0
+#define BRUTE_IMPOSSIBLE -1
+#define BRUTE_TIMEOUT    -2
+
+#define BRUTE_MAX_TIME 10
+
+int brute(void);
+
+#endif

sources/Generator/brute_comp.c

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+/* brute_comp.c
+ *
+ * Copyright (C) 2015  Giulio Zambon  - http://zambon.com.au/
+ *
+ */
+#include <stdio.h>
+#include <stdlib.h>
+#include <time.h>
+#include "brute.h"
+#include "brute_comp.h"
+#include "def.h"
+#include "inconsistent_grid.h"
+
+// This messages in clear must match the codes defined in brute_comp.h
+const char *brute_comp_err[] = {
+    /* 0 */ "same as reference",
+    /* 1 */ "different from reference",
+    /* 2 */ "timeout",
+    /* 3 */ "grid inconsistent",
+    /* 4 */ "puzzle impossible",
+    /* 5 */ "unknown result"
+    };
+
+int brute_comp() {
+  int result = BRUTE_COMP_PROBLEM;
+  int brute_result = brute();
+  switch (brute_result) {
+
+    case BRUTE_SUCCESSFUL:
+      result = BRUTE_COMP_OK;
+      for (int kk = 0; kk < 9 && result == BRUTE_COMP_OK; kk++) {
+        for (int jj = 0; jj < 9 && result == BRUTE_COMP_OK; jj++) {
+          if (solved[kk][jj] != grid[kk][jj]) result = BRUTE_COMP_DIFFERENT;
+          }
+        }
+      if (inconsistent_grid()) result = BRUTE_COMP_INCONSISTENT;
+      break;
+
+    case BRUTE_IMPOSSIBLE:
+      result = BRUTE_COMP_IMPOSSIBLE;
+      break;
+
+    case BRUTE_TIMEOUT:
+      result = BRUTE_COMP_TIMEOUT;
+      break;
+
+    default:
+      result = BRUTE_COMP_PROBLEM;
+      break;
+    }
+  return result;
+  }

sources/Generator/brute_comp.h

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+/* brute_comp.h
+ *
+ * Solves a Sudoku by executing brute() and then compares the result with
+ * the reference
+ *
+ * See below for the return codes
+ *
+ * Copyright (C) 2015  Giulio Zambon  - http://zambon.com.au/
+ *
+ */
+#ifndef BRUTE_COMPARE
+#define BRUTE_COMPARE
+
+// If you modify the following list, change brute_comp_err accordingly
+#define BRUTE_COMP_OK            0
+#define BRUTE_COMP_DIFFERENT     1
+#define BRUTE_COMP_TIMEOUT       2
+#define BRUTE_COMP_INCONSISTENT  3
+#define BRUTE_COMP_IMPOSSIBLE    4
+#define BRUTE_COMP_PROBLEM       5
+
+extern const char *brute_comp_err[];
+
+int brute_comp(void);
+
+#endif

sources/Generator/count_solved.c

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+/* count_solved.c
+ *
+ * Copyright (C) 2015  Giulio Zambon  - http://zambon.com.au/
+ *
+ */
+#include <stdio.h>
+#include <stdlib.h>
+#include "count_solved.h"
+#include "def.h"
+
+int count_solved() {
+  int result = 0;
+  for (int k = 0; k < 9; k++) {
+    for (int j = 0; j < 9; j++) {
+      if (grid[k][j] != 0) result++;
+      }
+    }
+  return result;
+  }

sources/Generator/count_solved.h

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+/* count_solved.h
+ *
+ * Counts the number of solved cells.
+ *
+ * Copyright (C) 2015  Giulio Zambon  - http://zambon.com.au/
+ *
+ */
+#ifndef COUNT_SOLVED
+#define COUNT_SOLVED
+
+int count_solved(void);
+
+#endif

sources/Generator/def.h

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+/* def.h
+ *
+ * Definitions and declarations
+ *
+ * Copyright (C) 2015  Giulio Zambon  - http://zambon.com.au/
+ *
+ */
+#ifndef DEF
+#define DEF
+
+// General definitions
+#define FALSE  0
+#define TRUE   1
+
+// Used in some strategies for clarity
+#define ROW 0
+#define COL 1
+#define BOX 2
+extern char *unit_names[3];
+
+// grid declarations
+extern char grid[9][9];
+extern char row[9][9][2];
+extern char col[9][9][2];
+extern char box[9][9][2];
+extern char solved[9][9];
+
+// Flags
+extern int silent;
+
+// Patch because Windows doesn't recognise srandom() and random()
+#ifdef __WIN32__
+#define srandom srand
+#define random rand
+#endif
+
+#endif

sources/Generator/display.c

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+/* display.c
+ *
+ * Copyright (C) 2015  Giulio Zambon  - http://zambon.com.au/
+ *
+ */
+#include <stdio.h>
+#include <stdlib.h>
+#include "def.h"
+#include "display.h"
+
+void display() {
+  char *h = "  ++---+---+---++---+---+---++---+---+---++";
+  char *hh = "  ++===+===+===++===+===+===++===+===+===++";
+  int jBase[] = {2, 6, 10, 15, 19, 23, 28, 32, 36};
+  printf("     0   1   2    3   4   5    6   7   8\n");
+  for (int k = 0; k < 9; k++) {
+    if (k%3 == 0) {
+      printf("%s\n", hh);
+      }
+    else {
+      printf("%s\n", h);
+      }
+    //                000 000 111  111 122 222  223 333 333
+    //                234 678 012  567 901 345  890 234 678
+    char top[42] = "||   |   |   ||   |   |   ||   |   |   ||";
+    char mid[42] = "||   |   |   ||   |   |   ||   |   |   ||";
+    char bot[42] = "||   |   |   ||   |   |   ||   |   |   ||";
+    char *displ[42] = {top, mid, bot};
+    for (int j = 0; j < 9; j++) {
+      if (grid[k][j] == 0) {
+        mid[jBase[j]+1] = ' ';
+        }
+      else {
+        mid[jBase[j]+1] = '0' + grid[k][j];
+        }
+      } // for (int j..
+    printf("  %s\n", displ[0]);
+    printf("%d %s\n", k, displ[1]);
+    printf("  %s\n", displ[2]);
+    }
+  printf("%s\n", hh);
+  }

sources/Generator/display.h

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+/* display.h
+ *
+ * Displays the sudoku grid.
+ *
+ * Copyright (C) 2015  Giulio Zambon  - http://zambon.com.au/
+ *
+ */
+#ifndef DISPLAY
+#define DISPLAY
+
+void display();
+
+#endif

sources/Generator/display_string.c

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+/* display_string.c
+ *
+ * Copyright (C) 2015  Giulio Zambon  - http://zambon.com.au/
+ *
+ */
+#include <stdio.h>
+#include <stdlib.h>
+#include "def.h"
+#include "display_string.h"
+
+void display_string(char *name) {
+  for (int k = 0; k < 9; k++) {
+    for (int j = 0; j < 9; j++) {
+      printf("%d", grid[k][j]);
+      }
+    }
+  if (name != NULL) printf(" \"%s\"", name);
+  printf("\n");
+  }

sources/Generator/display_string.h

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+/* display_string.h
+ *
+ * Displays the sudoku string.
+ *
+ * Copyright (C) 2015  Giulio Zambon  - http://zambon.com.au/
+ *
+ */
+#ifndef DISPLAY_STRING
+#define DISPLAY_STRING
+
+void display_string(char *name);
+
+#endif