added Exercise 6-3

Author: satyajitghana

Chapter-6/Exercise 6-3/io.c

@@ -30,8 +30,11 @@ int getword(char *word, int lim) {
     char *w = word;
 
     /* skip the whitespaces */
-    while (isspace(c = getch()))
+    /*while (isspace(c = getch()))
+        ;*/
+    while ((c = getch()) == ' ' || c == '\t')
         ;
+    //printf(" #%d# ", word[0]);
     if (c != EOF)
         *w++ = c;
     if (!isalpha(c)) {

Chapter-6/Exercise 6-3/itoa.c

@@ -1,8 +1,14 @@
-int itoa(char *s) {
-    int c, num = 0;
-    int *np = s;
+#include <stdio.h>
 
-    /* skip the whitespaces */
-    while ((c = *np++) == ' ' || c == '\t')
-        ;
+void itoa(int a, char *s) {
+    static int i = 0;
+    if (a < 0) {
+        s[i++] = '-';
+        a *= -1;
+    }
+    if (a > 0) {
+        itoa(a/10, s);
+        s[i++] = '0' + a%10;
+        //printf("%d %d\n", a, i++);
+    }
 }

Chapter-6/Exercise 6-3/itoa.h

@@ -0,0 +1,6 @@
+#ifndef ITOA_H
+#define ITOA_H
+
+void itoa(int, char*);
+
+#endif

Chapter-6/Exercise 6-3/main.c

@@ -4,6 +4,7 @@
 #include <string.h>
 #include "tree.h"
 #include "io.h"
+//#include "itoa.h"
 
 #define MAXWORD 100
 
@@ -19,8 +20,9 @@ int main(int argc, char **argv) {
     root = NULL;
     while (getword(word, MAXWORD) != EOF) {
         if (isalpha(word[0]))
-            root = addtree(root, word, itoa(lnum));
+            root = addtree(root, word, lnum);
 
+        //printf(" *%s* ", word);
         if (word[0] == '\n')
             lnum++;
     }

Chapter-6/Exercise 6-3/tree.c

@@ -4,21 +4,26 @@
 #include "io.h"
 #include "tree.h"
 
-/* addtree: add a node with w, at or below p */
-struct tnode *addtree(struct tnode *p, char *w) {
+/* addtree: add a node with w, line n, at or below p */
+struct tnode *addtree(struct tnode *p, char *w, int n) {
     int cond;
 
     if (p == NULL) {    /* a new word has arrived */
         p = talloc();
         p -> word = _strdup(w);
         p -> count = 1;
         p -> left = p -> right = NULL;
-    } else if ((cond = strcmp(w, p -> word)) == 0)
+        p -> lsize = 0;
+        p -> lnum [p -> lsize ++] = n;
+    } else if ((cond = strcmp(w, p -> word)) == 0) {
         p -> count++; /* repeated word */
+        if (lsearch(p -> lnum, n, p -> lsize) < 0)
+            p -> lnum[p -> lsize ++] = n;
+    }
     else if (cond < 0)
-        p -> left = addtree(p -> left, w);
+        p -> left = addtree(p -> left, w, n);
     else
-        p -> right = addtree(p -> right, w);
+        p -> right = addtree(p -> right, w, n);
     return p;
 }
 
@@ -27,6 +32,8 @@ void treeprint(struct tnode *p) {
     if (p != NULL) {
         treeprint(p -> left);
         printf("%4d %s\n", p -> count, p -> word);
+        for (int i = 0 ; i < p -> lsize ; i++)
+            printf("\t%4d\n", p -> lnum[i]);
         treeprint(p -> right);
     }
 }
@@ -35,3 +42,12 @@ void treeprint(struct tnode *p) {
 struct tnode *talloc(void) {
     return (struct tnode *) malloc(sizeof(struct tnode));
 }
+
+/* lsearch: linear search for ele in arr[0] ... arr[size] */
+int lsearch(int *arr, int ele, int size) {
+    for (int i = 0 ; i < size ; i++)
+        if (arr[i] == ele)
+            return i;
+    /* ele not found in arr */
+    return -1;
+}

Chapter-6/Exercise 6-3/tree.h

@@ -6,15 +6,18 @@
 struct tnode {          /* the tree node: */
     char *word;                 /* points to the text   */
     int count;                  /* number of occurences */
-    struct tnode *lnum ;        /* list of line number on which it occurs */
+    int lnum[MAXLNUMBERS];      /* list of line number on which it occurs */
+    int lsize;                  /* number of lines wheresword occurs */
     struct tnode *left;         /* left child           */
     struct tnode *right;        /* right child          */
 };
 
-struct tnode *addtree(struct tnode *, char *);
+struct tnode *addtree(struct tnode *, char *, int);
 
 void treeprint(struct tnode *p);
 
 struct tnode *talloc(void);
 
+int lsearch(int *, int, int);
+
 #endif