From 5b3aa21110191680627f0226ba313bc75f1a7937 Mon Sep 17 00:00:00 2001
From: Kyle K <kylek389@gmail.com>
Date: Tue, 16 Nov 2010 11:07:46 -0600
Subject: print to file, simplified mergesort

---
 sorts.c | 85 +++++++++++++++++++++++++++++++++++++++++++----------------------
 1 file changed, 57 insertions(+), 28 deletions(-)

diff --git a/sorts.c b/sorts.c
index 5dd49a2..f4bb9b3 100644
--- a/sorts.c
+++ b/sorts.c
@@ -11,7 +11,14 @@
 #include <string.h>
 #include <time.h>
 #include <assert.h>
-#define ARR_SIZE 10
+#define ARR_SIZE 20
+#define ARR_RANGE 10
+#define ELEM_LINE 10
+#define FNAME "sort.txt"
+#undef PRINT_FILE
+
+/* global */
+FILE *out = NULL;
 
 /* function prototypes */
 void insrt_sort(int *, int);
@@ -39,7 +46,7 @@ void mergesort(int a[], int low, int high)
 /* http://en.allexperts.com/q/C-1587/Merge-Sort-C.htm */
 void merge(int a[], int low, int high, int mid)
 {
-    int i, j, k, c[50];
+    int i, j, k, c[ARR_SIZE];
     i = low;
     j = mid + 1;
     k = low;
@@ -47,32 +54,16 @@ void merge(int a[], int low, int high, int mid)
     while ( (i <= mid) && (j <= high) )
     {
         if (a[i] < a[j])
-        {
-            c[k] = a[i];
-            k++;
-            i++;
-        }
+            c[k++] = a[i++];
         else
-        {
-            c[k] = a[j];
-            k++;
-            j++;
-        }
+            c[k++] = a[j++];
     }
 
     while (i <= mid)
-    {
-        c[k] = a[i];
-        k++;
-        i++;
-    }
+        c[k++] = a[i++];
 
     while (j <= high)
-    {
-        c[k] = a[j];
-        k++;
-        j++;
-    }
+        c[k++] = a[j++];
 
     for (i = low; i < k; i++)
         a[i] = c[i];
@@ -133,14 +124,27 @@ void prnt_arr(int *arr, int elem)
     if (arr == NULL)
         fputs("nothing to print", stderr);
 
+#ifdef PRINT_FILE
+    assert(out != NULL);
+
     int i;
-    for (i = 0; i < elem; i++)
+    for (i = 1; i < elem + 1; i++)
     {
-        printf("%d ", *(arr + i) );
-        if ( (i % 10 == 0) && i != 0)
+        fprintf(out, "%3d ", *(arr + i - 1) );
+        if ( (i % ELEM_LINE == 0) && i != 0)
+            fprintf(out, "\n");
+    }
+    fprintf(out, "\n");
+#else
+    int i;
+    for (i = 1; i < elem + 1; i++)
+    {
+        printf("%3d ", *(arr + i - 1) );
+        if ( (i % ELEM_LINE == 0) && i != 0)
             printf("\n");
     }
     printf("\n");
+#endif
 }
 
 int *mk_rand_arr(int elem, int range)
@@ -165,16 +169,41 @@ int *mk_rand_arr(int elem, int range)
 
 int main(int argc, char **argv)
 {
-    srand( (unsigned int )time(NULL) );
+    srand( (unsigned int ) time(NULL) );
+    int *arr = mk_rand_arr(ARR_SIZE, ARR_RANGE);
 
-    int *arr = mk_rand_arr(ARR_SIZE, 10);
+#ifdef PRINT_FILE
+    out = fopen(FNAME, "w");
+    if (out == NULL)
+    {
+        perror("fopen");
+        exit(-1);
+    }
+#endif
+
+#ifdef PRINT_FILE
+    fprintf(out, "unsorted:\n");
+#else
+    printf("unsorted:\n");
+#endif
     prnt_arr(arr, ARR_SIZE);
 
     //bubble_sort(arr, ARR_SIZE);
     //select_sort(arr, ARR_SIZE);
-    insrt_sort(arr, ARR_SIZE);
+    //insrt_sort(arr, ARR_SIZE);
+    mergesort(arr, 0, ARR_SIZE - 1);
+
+#ifdef PRINT_FILE
+    fprintf(out, "sorted:\n");
+#else
+    printf("sorted:\n");
+#endif
     prnt_arr(arr, ARR_SIZE);
 
+#ifdef PRINT_FILE
+    fclose(out);
+#endif
+
     return 0;
 }
 
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