add qsort and 4.11

2 files changed, 190 insertions, 0 deletions

diff --git a/4.11.c b/4.11.c
new file mode 100644
index 0000000..32bac92
--- /dev/null
+++ b/4.11.c
@@ -0,0 +1,113 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <ctype.h>
+#include <math.h>
+
+#define MAXOP 100
+#define NUMBER_SIG '0'
+
+double pop(void);
+void push(double f);
+char getop(char str[]);
+
+int 
+main(void)
+{
+  char str[MAXOP];
+  char type;
+  double op2;
+
+  while ((type = getop(str)) != EOF) {
+    switch (type) {
+      case NUMBER_SIG :
+        push(atof(str));
+        break;
+      case '+' :
+        push(pop() + pop());
+        break;
+      case '*' :
+        push(pop() * pop());
+        break;
+      case '-' :
+        op2 = pop();
+        push(pop() - op2);
+        break;
+      case '/' :
+        if ((op2 = pop()) == 0.0)
+          printf("Err: deviser cant be zero\n");
+        else 
+          push(pop() / op2);
+
+        break;
+      case '%' :
+        op2 = pop();
+        if (op2 != 0)
+          push(fmod(pop(), op2));
+        else 
+          printf("Err: deviser cant be zero\n");
+
+        break;
+      case '\n' :
+        printf("%.8g\n", pop());
+        break;
+      default :
+        printf("Err: unknown command\n");
+    }
+  }
+
+  return 0;
+}
+
+#define MAXVAL 100
+double val[MAXVAL];
+int sp = 0;
+
+double 
+pop(void)
+{
+  if (sp > 0)
+    return val[--sp];
+  else {
+    printf("Err: stack empty\n");
+    return 0.0;
+  }
+}
+
+void
+push(double f)
+{
+  if (sp < MAXVAL)
+    val[sp++] = f;
+  else
+    printf("Err: stack is full\n");
+}
+
+
+char 
+getop(char str[])
+{
+  static char buff = ' ';
+  char input;
+  int i;
+
+  /* ignore blanks */
+  for (input = buff, str[0] = buff; isblank(input);)
+    input = str[0] = getchar();
+  
+  buff = ' ';
+
+  /* return operator */
+  if (!isdigit(input) && input != '.')
+    return input;
+
+  /* collect digits*/
+  for (i = 1; i < MAXOP && (isdigit(input=getchar()) || input == '.'); i++)
+    str[i] = input;
+
+  str[i] = '\0';
+
+  if (input != EOF)
+    buff = input;
+
+  return NUMBER_SIG;
+}
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;
+}