add qsort and 4.11

1 files changed, 77 insertions, 0 deletions

diff --git a/qsort.c b/qsort.c
new file mode 100644
index 0000000..dbf234b
--- /dev/null
+++ b/qsort.c
@@ -0,0 +1,77 @@
+#include <stdio.h>
+
+void printia(int array[], int len);
+void qsort(int array[], int left, int right);
+void swap(int array[], int i, int j);
+
+int 
+main(void)
+{
+  /*               0  1  2  3  4  5  6  7  8  9*/
+  int array[10] = {9, 6, 1, 5, 3, 7, 0, 4, 2, 8};
+
+  printf("c> 0 1 2 3 4 5 6 7 8 9\n");
+  printia(array, sizeof(array)/sizeof(int));
+  qsort(array, 0, sizeof(array)/sizeof(int)-1);
+  printia(array, sizeof(array)/sizeof(int));
+
+  return 0;
+}
+
+void 
+printia(int array[], int len)
+{
+  int i;
+
+  printf("a> ");
+  
+  for (i = 0; i < len; i++)
+    printf("%d ", array[i]);
+
+  printf("\n");
+}
+
+void 
+qsort(int array[], int left, int right)
+{
+  int i, last;
+
+  if (left >= right)
+    return;
+
+  printf("1> array[%d] <=> array[%d] | %d <=> %d\n", left, (left+right)/2, array[left], array[(left+right)/2]);
+  swap(array, left, (left+right)/2);
+  printia(array, 10);
+  last  = left;
+
+  for (i = left+1; i <= right; i++)
+    if (array[i] < array[left]) {
+      printf("2> array[%d] <=> array[%d] | %d <=> %d\n", last+1, i, array[last+1], array[i]);
+      swap (array, ++last, i);
+      printia(array, 10);
+    }
+  printf("s> |---------<for loope>-+-------|\n");
+
+  printf("3> array[%d] <=> array[%d] | %d <=> %d\n", left, last, array[left], array[last]);
+  swap(array, left, last);
+  printia(array, 10);
+
+  qsort (array, left, last-1);
+  qsort(array, last+1, right);
+  printf("s> |------------<END>----+-------|\n");
+
+}
+
+void
+swap(int array[], int i, int j)
+{
+  int temp;
+
+  if (i == j)
+    printf("s> |---------<same swap>-+-------|\n");
+
+  temp = array[i];
+
+  array[i] = array[j];
+  array[j] = temp;
+}