K & R C Programs Exercise 6-4.

K and R C, Solution to Exercise 6-4:
K and R C Programs Exercises provides the solution to all the exercises in the C Programming Language (2nd Edition). You can learn and solve K&R C Programs Exercise.
Write a C Program that prints the distinct words in its input sorted into decreasing order of frequency of occurrence. Precede each word by its count. Read more about C Programming Language .

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#include<stdio.h>
#include<ctype.h>

#define MAXWORD 100
#define NDISTINCT 1000

struct tnode(
char *word;
int count;
struct tnode *addtree(struct tnode *, char *);
int getword(char *, int);
void sortlist(void);
void treestore(struct tnode *);
struct tnode *list[DISTINCT];
int ntn = 0;

/* print distinct words sorted in decreasing order of freq.*/
main()
{
struct tnode *root;
char word[MAXWORD]
int i;

root = NULL;
while(getword(word, MAXWORD) != EOF)
if(isalpha(word[0]))
root = addtree(root, word);
treestore(root);
sortlist();
for(i = 0;i < ntn; i++)
printf("%2d:%20sn",list[i]->count,list[i]->word);
return 0;
}

//getword: get next word or character from input
int getword(char *word, int lim)
{
int c, d, comment(void), getch(void);
void ungetch(int);
char *w = word;
while(isspace(c = getch()))
;
if(c !=EOF)
*w++ = c;
if(isalpha(c) || c == '-' || c == '#'){
for(; --lim > 0; w++)
if(!isalnum(*w = getch()) && *w != '-') {
ungetch(*w);
break;
}
}
else if(c == ''' || c == '\'){
for( ; --lim > 0; w++)
if(((*w = getch()) == '\')
*++w = getch();
else if(*w == c) {
w++;
break;
}else if(*w == EOF)
break;
}else if(c == '/')
if((d = getch()) == '*')
c = comment();
else
ungetch(d);
*w = '';
return c;
}


//comment: skip over comment and return a character
int comment()
{
int c;
while((c = getch()) != EOF)
if(c == '*')
if((c = getch()) == '/')
break;
else
ungetch(c);
return c;
}

//TREESTORE:STORE IN LIST[] POINTERS TO TREE NODES

void treestore(struct tnode *p)
{
if(p != NULL) {
treestore(p->left);
if(ntn < NDISTINCT)
list[ntn++] = p;
treestore(p->right);
}
}

//sortlist: sort list of pointers to tree nodes
void sortlist()
{
int gap, i,j;
struct tnode *temp;

for(gap = ntn/2;gap > 0;gap /= 2)
for(i = gap; i < ntn;i++)
for(j = i - gap;j >= 0;j -= gap) {
if((list[j]->count) >= (list[j+gap]->count))
break;
temp = list[j];
list[j] = list[j+gap];
list[j+gap] = temp;
}
}
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K & R C Programs Exercise 6-3

K and R C, Solution to Exercise 6-3:
K and R C Programs Exercises provides the solution to all the exercises in the C Programming Language (2nd Edition). You can learn and solve K&R C Programs Exercise.
C Program to Write a cross-referencer program that prints a list of all words in a document, and, for each word, a list of the line numbers on which it occurs. Remove noise words like “the”, “and,” and so on. Read more about C Programming Language .

/***********************************************************
* You can use all the programs on www.c-program-example.com
* for personal and learning purposes. For permissions to use the
* programs for commercial purposes,
* contact [email protected]
* To find more C programs, do visit www.c-program-example.com
* and browse!
* Original URL: http://www.c-program-example.com/2012/02/k-r-c-programs-exercise-6-3.html
* GitHub URL: https://github.com/snadahalli/cprograms/blob/master/knrc/knrc6_3.c
***********************************************************/

/** Write a cross-referencer program that prints a list of all words in a
* document, and, for each word, a list of the line numbers on which it
* occurs. Remove noise words like "the", "and," and so on.
**/

#include
#include
#include
#include

char *dupstr(char *s) {
char *p = NULL;
if(s != NULL){
p = malloc(strlen(s) + 1);
if(p) {
strcpy(p, s);
}
}
return p;
}

int i_strcmp(const char *s, const char *t) {
int diff = 0;
char cs = 0;
char ct = 0;

while(diff == 0 && *s != '' && *t != '') {
cs = tolower((unsigned char)*s);
ct = tolower((unsigned char)*t);
if(cs < ct) {
diff = -1;
}
else if(cs > ct) {
diff = 1;
}
++s;
++t;
}

if(diff == 0 && *s != *t) {
if(*s == '') {
diff = -1;
}
else {
diff = 1;
}
}

return diff;
}

struct linelist {
struct linelist *next;
int line;
};

struct wordtree {
char *word;
struct linelist *firstline;
struct wordtree *left;
struct wordtree *right;
};

void printlist(struct linelist *list) {
if(list != NULL) {
printlist(list->next);
printf("%6d ", list->line);
}
}

void printtree(struct wordtree *node) {
if(node != NULL) {
printtree(node->left);
printf("%18s ", node->word);
printlist(node->firstline);
printf("n");
printtree(node->right);
}
}

struct linelist *addlink(int line) {
struct linelist *new = malloc(sizeof *new);
if(new != NULL) {
new->line = line;
new->next = NULL;
}
return new;
}

void deletelist(struct linelist *listnode) {
if(listnode != NULL) {
deletelist(listnode->next);
free(listnode);
}
}

void deleteword(struct wordtree **node) {
struct wordtree *temp = NULL;
if(node != NULL) {
if(*node != '') {
if((*node)->right != NULL) {
temp = *node;
deleteword(&temp->right);
}
if((*node)->left != NULL) {
temp = *node;
deleteword(&temp->left);
}
if((*node)->word != NULL) {
free((*node)->word);
}
if((*node)->firstline != NULL) {
deletelist((*node)->firstline);
}
free(*node);
*node = NULL;
}
}
}

struct wordtree *addword(struct wordtree **node, char *word, int line) {
struct wordtree *wordloc = NULL;
struct linelist *newline = NULL;
struct wordtree *temp = NULL;
int diff = 0;

if(node != NULL && word != NULL) {
if(NULL == *node) {
node = malloc(sizeof **node);
if(NULL != *node) {
(*node)->left = NULL;
(*node)->right = NULL;
(*node)->word = dupstr(word);
if((*node)->word != NULL) {
(*node)->firstline = addlink(line);
if((*node)->firstline != NULL) {
wordloc = *node;
}
}
}
}
else {
diff = i_strcmp((*node)->word, word);
if(0 == diff) {

newline = addlink(line);
if(newline != NULL) {
wordloc = *node;
newline->next = (*node)->firstline;
(*node)->firstline = newline;
}
}
else if(0 < diff) {
temp = *node;
wordloc = addword(&temp->left, word, line);
}
else {
temp = *node;
wordloc = addword(&temp->right, word, line);
}
}
}

if(wordloc == NULL) {
deleteword(node);
}

return wordloc;
}


char *char_in_string(char *s, int c) {
char *p = NULL;

/* if there's no data, we'll stop */
if(s != NULL) {
if(c != '') {
while(*s != '' && *s != c) {
++s;
}
if(*s == c) {
p = s;
}
}
}
return p;
}

char *tokenise(char **s, char *delims) {
char *p = NULL;
char *q = NULL;

if(s != NULL && *s != '' && delims != NULL) {
/* pass over leading delimiters */
while(NULL != char_in_string(delims, **s)) {
++*s;
}
if(**s != '') {
q = *s + 1;
p = *s;
while(*q != '' && NULL == char_in_string(delims, *q)) {
++q;
}

*s = q + (*q != '');
*q = '';
}
}

return p;
}

int NoiseWord(char *s)
{
int found = 0;
int giveup = 0;

char *list[] = {
"a",
"an",
"and",
"be",
"but",
"by",
"he",
"I",
"is",
"it",
"off",
"on",
"she",
"so",
"the",
"they",
"you"
};

int top = sizeof list / sizeof list[0] - 1;
int bottom = 0;
int guess = top / 2;

int diff = 0;

if(s != NULL) {
while(!found && !giveup) {
diff = i_strcmp(list[guess], s);
if(0 == diff) {
found = 1;
}
else if(0 < diff) {
top = guess - 1;
}
else {
bottom = guess + 1;
}
if(top < bottom) {
giveup = 1;
}
else {
guess = (top + bottom) / 2;
}
}
}

return found;
}

char *GetLine(char *s, int n, FILE *fp) {
int c = 0;
int done = 0;
char *p = s;

while(!done && --n > 0 && (c = getc(fp)) != EOF) {
if((*p++ = c) == 'n') {
done = 1;
}
}

*p = '';
if(EOF == c && p == s) {
p = NULL;
}
else {
p = s;
}
return p;
}

#define MAXLINE 8192

int main(void) {
static char buffer[MAXLINE] = {0};
char *s = NULL;
char *word = NULL;
int line = 0;
int giveup = 0;
struct wordtree *tree = NULL;

char *delims = " tnrafv!"%^&*()_=+{}[]\|/,.<>:;#~?";

while(!giveup && GetLine(buffer, sizeof buffer, stdin) != NULL) {
++line;
s = buffer;
while(!giveup && (word = tokenise(&s, delims)) != NULL) {
if(!NoiseWord(word)) {
if(NULL == addword(&tree, word, line)) {
printf("Error adding data into memory. Giving up.n");
giveup = 1;
}
}
}
}

if(!giveup) {
printf("%18s Line Numbersn", "Word");
printtree(tree);
}

deleteword(&tree);
return 0;
}
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C program to implement stack.

Data structures using C,
Write a C program to implement stack. Stack is a data structure in which the objects are arranged in a non linear order. In stack, elements are added or deleted from only one end, i.e. top of the stack. Stack is a LIFO data structure. LIFO – Last in First Out Perform PUSH(insert operation), POP(Delete operation) and Display stack . Read more about C Programming Language .

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* You can use all the programs on www.c-program-example.com
* for personal and learning purposes. For permissions to use the
* programs for commercial purposes,
* contact [email protected]
* To find more C programs, do visit www.c-program-example.com
* and browse!
*
* Happy Coding
***********************************************************/



#include <stdio.h>
#include <conio.h>
#define MAXSIZE 5

struct stack /* Structure definition for stack */
{
int stk[MAXSIZE];
int top;
};

typedef struct stack STACK;
STACK s;

/* Function declaration/Prototype*/

void push (void);
int pop(void);
void display (void);

void main ()
{
int choice;
int option = 1;

clrscr ();

s.top = -1;

printf ("STACK OPERATIONn");
while (option)
{
printf ("------------------------------------------n");
printf (" 1 --> PUSH n");
printf (" 2 --> POP n");
printf (" 3 --> DISPLAY n");
printf (" 4 --> EXIT n");
printf ("------------------------------------------n");

printf ("Enter your choicen");
scanf ("%d", &choice);

switch (choice)
{
case 1: push();
break;
case 2: pop();
break;
case 3: display();
break;
case 4: return;
}

fflush (stdin);
printf ("Do you want to continue(Type 0 or 1)?n");
scanf ("%d", &option);
}
}

/*Function to add an element to the stack*/
void push ()
{
int num;
if (s.top == (MAXSIZE - 1))
{
printf ("Stack is Fulln");
return;
}
else
{
printf ("Enter the element to be pushedn");
scanf ("%d", &num);
s.top = s.top + 1;
s.stk[s.top] = num;
}
return;
}


/*Function to delete an element from the stack*/
int pop ()
{
int num;
if (s.top == - 1)
{
printf ("Stack is Emptyn");
return (s.top);
}
else
{
num = s.stk[s.top];
printf ("poped element is = %dn", s.stk[s.top]);
s.top = s.top - 1;
}
return(num);
}

/*Function to display the status of the stack*/
void display ()
{
int i;
if (s.top == -1)
{
printf ("Stack is emptyn");
return;
}
else
{
printf ("nThe status of the stack isn");
for (i = s.top; i >= 0; i--)
{
printf ("%dn", s.stk[i]);
}
}
printf ("n");
}
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