Sorting word occurrence in string C programming - c

I have been stuck on this for a while now. I wrote my program to count word occurrence in an inputted string by the user as well to sort the words alphabetically. My issue is my program runs perfectly only if there are spaces in between the words inputted. For example, if I input "to to," my program will count those two words as two different words due to the comma rather than counting it as one word in "to" as I would like it to. It is that issue for all of my delimiters in the array const char delim[]. How can I fix this issue in my program? I really appreciate any help! My code is down below:
Edit: I took Bob's suggestion to use strchr() and it worked! My only issue is my program outputs the count for delimiters now. I was thinking of possibly writing an if statement when comparing words[i] with words[j] to see if they have the same value. Is that the best approach to it?
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <ctype.h>
const char delim[] = ", . - !*()&^%$##<> ? []{}\\ / \"";
#define SIZE 1000
int main(){
char string[SIZE], words[SIZE][SIZE], temp[SIZE];
int a = 0, i = 0, j = 0, k = 0, n = 0, count;
int c = 0, cnt[26] = { 0 };
int word = 0;
int x;
printf("Enter your input string:");
fgets(string, SIZE, stdin);
string[strlen(string) - 1] = '\0';
lower(string);
/*extracting each and every string and copying to a different place */
while (string[i] != '\0'){
if (strchr(", . - !*()&^%$##<> ? []{}\\ / \"", string[i]) != NULL){
words[j][k] = '\0';
k = 0;
j++;
}else {
words[j][k++] = string[i];
}
i++;
}
words[j][k] = '\0';
n = j;
printf("Number of occurences of each word unsorted:\n");
i = 0;
/* find the frequency of each word and print the results */
while (i <= n) {
count = 1;
if (i != n) {
for (j = i + 1; j <= n; j++) {
if (strcmp(words[i], words[j]) == 0) {
count++;
for (a = j; a <= n; a++)
strcpy(words[a], words[a + 1]);
n--;
}
}//for
}
//word == strtok(string, delim);
/* count - indicates the frequecy of word[i] */
printf("%s\t%d\n", words[i], count);
i = i + 1;
}//while
printf("Alphabetical Order:\n");
/* sort the words in the given string */
for (i = 0; i < n; i++){
strcpy(temp, words[i]);
for (j = i + 1; j <= n; j++){
if (strcmp(words[i], words[j]) > 0){
strcpy(temp, words[j]);
strcpy(words[j], words[i]);
strcpy(words[i], temp);
}
} //inner for
} //outer for
i = 0;
while (i <= n) {
count = 1;
if (i != n) {
for (j = i + 1; j <= n; j++) {
if (strcmp(words[i], words[j]) == 0) {
count++;
}
}
}
printf("%s\n", words[i]);
i = i + count;
}
}

Strip every word of that delimeter before comparing. Actually you don't even need a list of delimeters because words are 'alpha' other than that it's a delimeter.

Please try this, it works, it is an extract of your own code, a little bit modified, it will give you the count, then you have to write the rest, have fun.
#include <string.h>
#define YES 1
#define NO 0
int main( )
{
char string[1000];
int i = 0;
int j = 0;
int is_this_a_word = 0;
strcpy( string, " to or not ,tobe" );
while ( string[i++] != '\0' )
{
if ( strchr( ", . - !*()&^%$##<> ? []{}\\ / \"", string[i] ) != NULL )
{
is_this_a_word = NO;
}
else
{
if ( ! is_this_a_word )
{
is_this_a_word = YES;
j++;
}
}
}
printf( "I counted %d words", j );
getchar( );
}

Related

Problem with counting elements in the list of names

I have made one program, where you enter a few characters (10 max). It makes you a list, count average length of surnames, tell about how much different names. But the problem is, when I enter the last number (10) - it sorts me it incorrectly (like 1, 10, 2, 3, 4, 5, 6, 7, 8, 9). Beneath I will present my code.
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
struct people {
char num[2];
char surname[20];
char name[10];
} peoples[10], c;
int main()
{
int i, j, k = 0, l = 0, m = 0, n = 0;
float s = 0;
char str[100];
system("chcp 1251 > nul");
for (i = 0, j = 0; i < 10; i++, j++)
{
printf("Enter number, surname, name %d of your human: ", i + 1);
gets(str);
while (str[n] != '\n')
{
if (str[n] != ' ')
{
peoples[j].num[k] = str[n];
}
else
break;
n++;
k++;
}
n++;
k = 0;
while (str[n] != '\n')
{
if (str[n] != ' ')
{
peoples[j].surname[k] = str[n];
}
else
break;
n++;
k++;
}
n++;
k = 0;
while (str[n] != '\n')
{
if (str[n] != '\0')
{
peoples[j].name[k] = str[n];
}
else
break;
n++;
k++;
}
n = 0;
k = 0;
}
for (i = 0; i < 10; i++)
{
for (j = i + 1; j < 10; j++)
{
if (!strcmp(peoples[i].name, peoples[j].name))
m = 1;
}
if (m == 0)
l++;
m = 0;
s = s + strlen(peoples[i].surname);
}
for (i = 0; i < 9; i++)
for (j = 0; j < 9; j++)
if (strcmp(peoples[j].num, peoples[j+1].num) > 0)
{
c = peoples[j+1];
peoples[j+1] = peoples[j];
peoples[j] = c;
}
for (i = 0; i < 10; i++)
{
printf("%s ", peoples[i].num);
printf("%s ", peoples[i].name);
printf("%s ", peoples[i].surname);
printf("\n");
}
printf("\nYou have %d different names\n", l);
printf("Avarege lenght of surname is = %f\n", s / 10);
}
If you want to give numeric input, then use actual numeric data.
Change the num field to become an int instead of a single-character string:
struct people {
int num;
char surname[20];
char name[10];
};
Use fgets to read the line:
fgets(str, sizeof str, stdin);
[Error checking left as exercise for reader]
Then use e.g. sscanf for parse your string:
sscanf(str, "%d %s %s", &peoples[j].num, &peoples[j].name, &peoples[j].name);
[Error checking left as exercise for reader]
And finally, instead of doing your own sorting use the standard qsort function:
qsort(peoples, 10, sizeof(struct people), &compare_people_num);
With the comparison function being something like this:
int compare_people_num(const void *a, const void *b)
{
const struct people *p1 = a;
const struct people *p2 = b:
return p1->num - p2->num; // Change order to reverse sort
}
Using sscanf and qsort will make your code much simpler and easier to understand.

trying to use strcmp in if function for counting anagrams in a sentence

hii guys i need a serious help
i m trying to write a code for finding anagrams in input sentence
but when the if function is getting strcmp it stops and its not accepting the condition. any body know why is that happening
Basically my code supposed to do two things one is taking a sentence from the user and making the words appear in the Backwoods order two Its need to take the whole sentence and look for anagrams ( anagram means that there is the same letters but in a different order for example this and shit are anagrams) thank you very much for your help :)
#include<stdio.h>
#include<stdlib.h>
#include<string.h>
void main()
{
int index_for_word_start, words_num = 1,amount_of_letters;
int i, j, k;
char inpot_Sentence[1001], temp_letters;
char **words,**sorting_words;
int counter = 0,counter_max_for_anegram=0;
printf_s("Please enter the sentence, and then press Enter:\n");
gets(inpot_Sentence);
/////////////////////////////makeing the sentence backwards///////////////////////
for (i = 0; inpot_Sentence[i] != '\0'; i++) //loop for counting how many words(it will be use to know how many pointer we need)
{
if (inpot_Sentence[i] == ' ')
{
words_num++;
}
}
words = (char **)malloc(sizeof(char *)*words_num); //malloc for pointers that point on the pointer of the word
index_for_word_start = 0;
for (j = 0; j<words_num; j++)
{
for (i = index_for_word_start; inpot_Sentence[i] != ' '; i++)
{
if (!inpot_Sentence[i]) //if the user didnt put any word(break)
{
break;
}
}
words[j] = (char*)malloc(sizeof(char)*(i - index_for_word_start + 1)); //malloc of pointers that point on each word
strncpy_s(words[j], i - index_for_word_start+1, &inpot_Sentence[index_for_word_start], i - index_for_word_start); //copy the words from inpot sentence to array
words[j][i - index_for_word_start] = 0; //puts '\0' after the word copy ends
index_for_word_start = i + 1;
}
printf_s("\nThe reverse sentence is:\n");
for (i = words_num - 1; i >= 0; i--) //print the words in backwards Sequence
{
printf("%s ", words[i]);
}
putchar('\n');
i = 0;
/////////////////////anegrams check///////////////////////
for (j = 0; j < words_num; j++) //loops that Arrange the array by haski value
{
amount_of_letters = strlen(words[j]);
for ( i = 0; i < amount_of_letters; i++)
{
for (k = 0; k < amount_of_letters; k++)
{
if (words[j][i]<words[j][k])
{
temp_letters = words[j][i];
words[j][i] = words[j][k];
words[j][k] = temp_letters;
}
}
}
printf_s("this is words %s\n", words[j]);
}i = 0;
for ( j = 0; j < words_num-1; j++)
{
for ( i = 0; i < words_num-1; i++)
{
if (!strcmp(words[j],words[i]) && (i!=j) && (strcmp(words[j],"\0")))
{
counter++;
words[i] = 0;
}
else
{
break;
}
}
if (counter>counter_max_for_anegram)
{
counter_max_for_anegram = counter;
}
counter = 0;
}
printf_s("%d\n", counter_max_for_anegram);
for ( j = 0; j < words_num; j++)
{
free(words[j]);
}
free(words);
}
#include <stdio.h>
#include <string.h>
int check_anagram(char[],char[]);
int main()
{
char a[100],b[100];
int flag;
puts("Enter the first string");
fgets(a,100,stdin);
a[strcspn(a, "\r\n")] = '\0';
puts("Enter the second string");
fgets(b,100,stdin);
b[strcspn(b, "\r\n")] = '\0';
flag=check_anagram(a,b);
if(flag)
printf("%s and %s are anagrams",a,b);
else
printf("%s and %s are not anagrams",a,b);
}
int check_anagram(char a[], char b[])
{
int first[26]={0},second[26]={0},c=0;
while(a[c]!='\0')
{
first[a[c]-'a']++;
c++;
}
c=0;
while(b[c]!='\0')
{
second[b[c]-'a']++;
c++;
}
for(c=0;c<26;c++)
{
if(first[c]!=second[c])
return 0;
}
return 1;
}

how to split words in a string in c?

I need to build a program that receives up to 30 chars from the user, and then to play with it.
For example, I need to reverses the sentence and then print it, or to rotate it.
I have been trying to copy the words of the sentence one by one to a matrix of [30][31], but it does not working... any ideas?
I cannot use pointers...
thanks for the help :)
#include <stdio.h>
#include <string.h>
void main(){
int i=0,
j=0,
wrongData=0,
charCounter=0,
word=0,
letter=0;
char st[100],
arr[100]={0},
mat[30][31]={0};
printf("Please, enter your sentence >");
gets(st);
while(i<strlen(st)){
if('A'<=st[i] && st[i]<='Z'){
charCounter++;
arr[j] = st[i];
i++;
j++;
} else if(st[i]==' '){
arr[j] = ' ';
i++;
j++;
while(st[i] == ' '){
i++;
}
} else if(st[i]=='\0'){
arr[j] = '\0';
break;
} else {
puts("ERROR: Incorrect data, try again.");
wrongData=1;
break;
}
if(wrongData==0){
if(charCounter>30){
puts("ERROR: Incorrect data, try again.");
}
}
}
puts(st);
puts(arr);
if(arr[j]==' '){
word++;
}
while(arr[j]!=' ' && letter<32){
strcpy(mat[word],arr);
}
if(arr[j]=='\0'){
mat[word][letter]=arr[j];
}
puts(mat[word]);
}
Taking into account your comment
the problem is that i need to reverse the words not the letters... for
example: if the string is cats hates dogs, i need to get at the end
dogs hates cats
then I think you mean something as the following
#include <stdio.h>
#include <ctype.h>
#include <string.h>
char * reverse_words( char s[] )
{
for ( char *p = s, *q = s; *p; p = q )
{
while ( isspace( ( unsigned char )*p ) ) ++p;
q = p;
while ( *q && !isspace( ( unsigned char )*q ) ) ++q;
for ( size_t i = 0; i < ( q - p ) / 2; i++ )
{
char c = p[i];
p[i] = q[-i-1];
q[-i-1] = c;
}
}
for ( size_t i = 0, n = strlen( s ); i < n / 2; i++ )
{
char c = s[i];
s[i] = s[n-i-1];
s[n-i-1] = c;
}
return s;
}
int main( void )
{
char s[] = "cats hates dogs";
puts( s );
puts( reverse_words( s ) );
return 0;
}
The program output is
cats hates dogs
dogs hates cats
Here is another approach. The idea is to go through the string and record the index where each word starts and ends. Then the words can be printed in reverse order afterwards. (btw - it will also be easy to rotate the words).
#include<stdio.h>
#include <string.h>
int main() {
char st[100] = "here we go again";
int start[30] = { 0 };
int end[30] = { 0 };
int count = 0;
int len = strlen(st);
int i, j;
// Find start and end index of each word
start[0] = 0;
for(i = 0; i < len; ++i)
{
if (st[i] == ' ')
{
end[count] = i;
++count;
start[count] = i + 1;
}
}
end[count] = len;
// Print the words in reverse order
for(i=count; i >= 0; --i)
{
for (j = start[i]; j < end[i]; ++j)
{
printf("%c", st[j]);
}
printf(" ");
}
printf("\n");
return 0;
}
output:
again go we here
fix your approach like this:
#include <stdio.h>
//#include <string.h>
#define MAX_LEN 30
int main(void){
int i, j, n, word;
char st[100], arr[100], mat[MAX_LEN / 2][MAX_LEN + 1];
printf("Please, enter your sentence (up to %d chars and A-Z or space)\n>", MAX_LEN);fflush(stdout);
scanf("%99[^\n]%*c", st);
//validate and reduce of spaces
for(j = i = 0; st[i]; ++i){
if(i > MAX_LEN){
fputs("ERROR: Incorrect data, try again.\n", stderr);
return 1;
}
if('A'<=st[i] && st[i]<='Z'){
arr[j++] = st[i];
} else if(st[i]==' '){
arr[j++] = ' ';
while(st[++i] == ' ')//Skip a continuous space
;
--i;//one back for next loop
} else {
fputs("ERROR: Incorrect data, try again.\n", stderr);
return 1;
}
}
arr[j] = '\0';//st[i]=='\0' never become true in loop
#if DEBUG
puts(st);
puts(arr);
#endif
//split to word
for(word = j = i = 0; arr[i];){
while(arr[i] == ' ')
++i;//skip space
while(arr[i] != ' ' && arr[i] != '\0')
mat[word][j++] = arr[i++];
mat[word++][j] = '\0';
j = 0;
}
#if DEBUG
for(i = 0; i < word; ++i)
puts(mat[i]);
#endif
puts("reverse word");
for(i = 0; i < word; ++i){
if(i)
putchar(' ');
printf("%s", mat[word-1-i]);
}
puts("\nrotate word");
printf("Please, enter number of rotate\n>");fflush(stdout);
scanf("%d", &n);
for(i = 0; i < word; ++i){
if(i)
putchar(' ');
printf("%s", mat[(i+n)%word]);//rotate left
}
}

Sorting words out in a string array

My program is designed to allow the user to input a string and my program will output the number of occurrences of each letters and words. My program also sorts the words alphabetically.
My issue is: I output the words seen (first unsorted) and their occurrences as a table, and in my table I don't want duplicates. SOLVED
For example, if the word "to" was seen twice I just want the word "to" to appear only once in my table outputting the number of occurrences.
How can I fix this? Also, why is it that i can't simply set string[i] == delim to apply to every delimiter rather than having to assign it manually for each delimiter?
Edit: Fixed my output error. But how can I set a condition for string[i] to equal any of the delimiters in my code rather than just work for the space bar? For example on my output, if i enter "you, you" it will out put "you, you" rather than just "you". How can I write it so it removes the comma and compares "you, you" to be as one word.
Any help is appreciated. My code is below:
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
const char delim[] = ", . - !*()&^%$##<> ? []{}\\ / \"";
#define SIZE 1000
void occurrences(char s[], int count[]);
void lower(char s[]);
int main()
{
char string[SIZE], words[SIZE][SIZE], temp[SIZE];
int i = 0, j = 0, k = 0, n = 0, count;
int c = 0, cnt[26] = { 0 };
printf("Enter your input string:");
fgets(string, 256, stdin);
string[strlen(string) - 1] = '\0';
lower(string);
occurrences(string, cnt);
printf("Number of occurrences of each letter in the text: \n");
for (c = 0; c < 26; c++){
if (cnt[c] != 0){
printf("%c \t %d\n", c + 'a', cnt[c]);
}
}
/*extracting each and every string and copying to a different place */
while (string[i] != '\0')
{
if (string[i] == ' ')
{
words[j][k] = '\0';
k = 0;
j++;
}
else
{
words[j][k++] = string[i];
}
i++;
}
words[j][k] = '\0';
n = j;
printf("Unsorted Frequency:\n");
for (i = 0; i < n; i++)
{
strcpy(temp, words[i]);
for (j = i + 1; j <= n; j++)
{
if (strcmp(words[i], words[j]) == 0)
{
for (a = j; a <= n; a++)
strcpy(words[a], words[a + 1]);
n--;
}
} //inner for
}
i = 0;
/* find the frequency of each word */
while (i <= n) {
count = 1;
if (i != n) {
for (j = i + 1; j <= n; j++) {
if (strcmp(words[i], words[j]) == 0) {
count++;
}
}
}
/* count - indicates the frequecy of word[i] */
printf("%s\t%d\n", words[i], count);
/* skipping to the next word to process */
i = i + count;
}
printf("ALphabetical Order:\n");
for (i = 0; i < n; i++)
{
strcpy(temp, words[i]);
for (j = i + 1; j <= n; j++)
{
if (strcmp(words[i], words[j]) > 0)
{
strcpy(temp, words[j]);
strcpy(words[j], words[i]);
strcpy(words[i], temp);
}
}
}
i = 0;
while (i <= n) {
count = 1;
if (i != n) {
for (j = i + 1; j <= n; j++) {
if (strcmp(words[i], words[j]) == 0) {
count++;
}
}
}
printf("%s\n", words[i]);
i = i + count;
}
return 0;
}
void occurrences(char s[], int count[]){
int i = 0;
while (s[i] != '\0'){
if (s[i] >= 'a' && s[i] <= 'z')
count[s[i] - 'a']++;
i++;
}
}
void lower(char s[]){
int i = 0;
while (s[i] != '\0'){
if (s[i] >= 'A' && s[i] <= 'Z'){
s[i] = (s[i] - 'A') + 'a';
}
i++;
}
}
I have the solution to your problem and its name is called Wall. No, not the type to bang your head against when you encounter a problem that you can't seem to solve but for the Warnings that you want your compiler to emit: ALL OF THEM.
If you compile C code with out using -Wall then you can commit all the errors that people tell you is why C is so dangerous. But once you enable Warnings the compiler will tell you about them.
I have 4 for your program:
for (c; c< 26; c++) { That first c doesn't do anything, this could be written for (; c < 26; c++) { or perhaps beter as for (c = 0; c <26; c++) {
words[i] == NULL "Statement with no effect". Well that probably isn't what you wanted to do. The compiler tells you that that line doesn't do anything.
"Unused variable 'text'." That is pretty clear too: you have defined text as a variable but then never used it. Perhaps you meant to or perhaps it was a variable you thought you needed. Either way it can go now.
"Control reaches end of non-void function". In C main is usually defined as int main, i.e. main returns an int. Standard practice is to return 0 if the program successfully completed and some other value on error. Adding return 0; at the end of main will work.
You can simplify your delimiters. Anything that is not a-z (after lower casing it), is a delimiter. You don't [need to] care which one it is. It's the end of a word. Rather than specify delimiters, specify chars that are word chars (e.g. if words were C symbols, the word chars would be: A-Z, a-z, 0-9, and _). But, it looks like you only want a-z.
Here are some [untested] examples:
void
scanline(char *buf)
{
int chr;
char *lhs;
char *rhs;
char tmp[5000];
lhs = tmp;
for (rhs = buf; *rhs != 0; ++rhs) {
chr = *rhs;
if ((chr >= 'A') && (chr <= 'Z'))
chr = (chr - 'A') + 'a';
if ((chr >= 'a') && (chr <= 'z')) {
*lhs++ = chr;
char_histogram[chr] += 1;
continue;
}
*lhs = 0;
if (lhs > tmp)
count_string(tmp);
lhs = tmp;
}
if (lhs > tmp) {
*lhs = 0;
count_string(tmp);
}
}
void
count_string(char *str)
{
int idx;
int match;
match = -1;
for (idx = 0; idx < word_count; ++idx) {
if (strcmp(words[idx],str) == 0) {
match = idx;
break;
}
}
if (match < 0) {
match = word_count++;
strcpy(words[match],str);
}
word_histogram[match] += 1;
}
Using separate arrays is ugly. Using a struct might be better:
#define STRMAX 100 // max string length
#define WORDMAX 1000 // max number of strings
struct word {
int word_hist; // histogram value
char word_string[STRMAX]; // string value
};
int word_count; // number of elements in wordlist
struct word wordlist[WORDMAX]; // list of known words

how to perform reversing a sentence Word by Word in C?

#include <stdio.h>
int main(void)
{
int i,j;
int wordstart = -1;
int wordend = -1;
char words[]= "this is a test";
char temp;
// Reverse each word
for (i = 0; i < strlen(words); ++i)
{
wordstart = -1;
wordend = -1;
if(words[i] != ' ')
wordstart = i;
for (j = wordstart; j < strlen(words); ++j)
{
if(words[j] == ' ')
{
wordend = j - 1;
break;
}
}
if(wordend == -1)
wordend = strlen(words);
for (j = wordstart ; j <= (wordend - wordstart) / 2; ++j)
{
temp = words[j];
words[j] = words[wordend - (j - wordstart)];
words[wordend - (j - wordstart)] = temp;
}
i = wordend;
printf("reversed string is %s:", words);
}
}
I tried in this way but i am getting this output:
siht is a test
my expected output is:
test a is this
I would appreciate if some one could come with a different approach for which time complexity is very less or correct me if it is the right approach. Thanks
Perhaps this belongs on the code review site instead?
Your approach seems very efficient to me (except that I would only call strlen(words) once and save the result in a register).
Two possible bugs look like:
wordend = strlen(words);
should be
wordend = strlen(words)-1;
and
for(j = wordstart ; j <= (wordend - wordstart) / 2 ; ++j) {
should be
for(j = wordstart ; j <= (wordend + wordstart) / 2 ; ++j) {
Final code looks like (with some extra {}):
#include <stdio.h>
int main(int argc,char *argv[])
{
int i,j;
char words[]= "this is a test";
int L=strlen(words);
// Reverse each word
for(i = 0; i < L; ++i) {
int wordstart = -1;
int wordend = -1;
if(words[i] != ' ')
{
wordstart = i;
for(j = wordstart; j < L; ++j) {
if(words[j] == ' ') {
wordend = j - 1;
break;
}
}
if(wordend == -1)
wordend = L-1;
for(j = wordstart ; j <= (wordend + wordstart) / 2 ; ++j) {
char temp = words[j];
words[j] = words[wordend - (j - wordstart)];
words[wordend - (j - wordstart)] = temp;
}
i = wordend;
}
}
printf("reversed string is %s:",words);
return 0;
}
You can create a double linked list as a base data structure. Then, iterate through the words and insert them in the list as you find them.
When you reach the end of the sentence, simply traverse the list backwards and print the words as you go through them
Simply we can just use a n*1 2D character array tailored to suit our needs!!!
#include <stdlib.h>
int main()
{
char s[20][20];
int i=0, length=-1;
for(i=0;;i++)
{
scanf("%s",s[i]);
length++;
if(getchar()=='\n')
break;
}
for(i=length;i>=0;i--)
printf("%s ",s[i]);
return 0;
}
Start tokenizing the line from the last character and continue to the first character. Keep one pointer anchored at the base of the current word, and another pointed which will decrease while a word start is not found. When you find a word start while scanning like this, print from the word start pointer to the word end anchor. Update the word end anchor to the previous character of the current word start char.
You might want to skip the blankspace characters while scanning.
UPDATE
This is a quick implementation:
#include <stdio.h>
#include <ctype.h>
#include <string.h>
#define MAX_BUF 256
void show_string (char *str, int i, int n)
{
while (i <= n)
{
printf ("%c", str[i]);
i++;
}
}
int main (void)
{
char str[MAX_BUF];
int end_anchor, start_ptr;
int state;
printf ("\nEnter a string: ");
scanf (" %[^\n]", str);
start_ptr = strlen (str) - 1;
end_anchor = start_ptr;
state = 0;
while (start_ptr >= -1)
{
switch (state)
{
case 0:
if ((!isspace (str[start_ptr]) && (start_ptr >= 0)))
{
start_ptr--;
}
else
{
state = 1;
}
break;
case 1:
show_string (str, start_ptr + 1, end_anchor);
state = 2;
start_ptr--;
printf (" ");
break;
case 2:
if (!isspace (str[start_ptr]))
{
state = 0;
end_anchor = start_ptr;
}
else
{
start_ptr--;
}
break;
}
}
printf ("\n");
return 0;
}
The end_anchor points to each end word, and the start_ptr finds the start of the word of which the end is held by end_anchor. When we find a word start (by blankspace characters or start_ptr = -1), we print all the characters from start_ptr + 1 to end_anchor. The + 1 is because of the implementation: start_ptr points to the blankspace character, and the print routine will print all the characters from i to n. Once we have detected one blank space we print it and we skip adjacent blankspaces (in case 2) and preserve only one which is manually printed. Once a non blankspace is detected, we have got another word end, for which we set the end_anchor to this index in the case 2, and set state = 0 , so that we can search for the word start again.
if(words[i] != ' ')
wordstart = i;
This statement what about the else part? if words[i] == ' ', and wordstart remains -1.
So maybe try to use:
while (words[i] && words[i] == ' ') ++i;
if (!words[i])
break;
wordstart = i;
Then you should output the result out of the i loop.
Finally, if you want to get the result you expected, you should reverse the whole sentence once more, with the way you used in the loop.
I would use write function similar to strrchr for finding last occurence of ' ', if its found print word that follows, rewrite this ' ' with '\0' and repeat it in loop till no more words are found. At the end I would print the content of this string again because there is most likely no ' ' before the first word.
I would write own function instead of strrchr because strrchr calculates the lenght of the given string, which is redundant in this case. This length doesn't have to be calculated more than once.
Here's the code:
char* findLastWord(char* str, int* len)
{
int i;
for (i = *len - 1; i >= 0; --i)
{
if (str[i] == ' ')
{
str[i] = '\0';
if (i < *len - 1)
{
*len = i - 1;
return &str[i + 1];
}
}
}
return NULL;
}
int main (int argc, char *argv[])
{
char str[] = " one two three four five six ";
int len = strlen(str);
char* lastWord = findLastWord(str, &len);
while (lastWord != NULL)
{
printf("%s\n", lastWord);
lastWord = findLastWord(str, &len);
}
if (len > 1)
printf("%s\n", str);
return 0;
}
output:
six
five
four
three
two
one
Hope this helps ;)
#include<stdio.h>
#include<string.h>
void reverse(char *str, size_t len)
{
char tmp;
size_t beg, end;
if (len <=1) return;
for (beg=0,end=len; beg < --end ; beg++) {
tmp = str[beg];
str[beg] = str[end];
str[end] = tmp;
}
}
int main(void)
{
char sentence[] = "one two three four five";
size_t pos, len;
printf("Before:%s\n",sentence);
for (pos = len= 0; sentence[pos]; pos += len) {
pos += strspn( sentence+pos, " \t\n" );
len = strcspn( sentence+pos, " \t\n" );
reverse ( sentence + pos, len );
}
reverse ( sentence , pos );
printf("After:%s\n",sentence);
return 0;
}
#include <iostream>
#include <string>
using namespace std;
char* stringrev(char s[], int len)
{
char *s1 = (char*)malloc(len+1);
int i=0;
while (len>0)
{
s1[i++] = s[--len];
}
s1[i++] = '\0';
return s1;
}
void sentrev(char s[], int len)
{
int i=0; int j=0;
char *r = (char*)malloc(len+1);
while(1)
{
if(s[j] == ' ' || s[j] == '\0')
{
r = stringrev(s+i, j-i);
i = j+1;
cout<<r<<" ";
}
if (s[j] == '\0')
break;
j++;
}
}
int main()
{
char *s = "this is a test";
char *r = NULL;
int len = strlen(s);
cout<<len<<endl;
r = stringrev(s, len);
cout<<r<<endl;
sentrev(r, len);
return 0;
}
The above code snap reverse the sentence, using char *r
and printing cout<
#include<stdio.h>
#include<conio.h>
#include<string.h>
int main()
{
char st[50], rst[50];
printf("Enter the sentence...\n");
gets(st);
int len=strlen(st), p;
int j=-1,k;
p=len;
for(int i=(len-1); i>=0; i--)
{
//searching for space or beginning
if(st[i]==' ')
{
//reversing and storing each word except the first word
for(k=i+1;k<p;k++)
{
//printf("%c",st[k]);
rst[++j]=st[k];
}
j++;
rst[j]=' ';
printf("\n");
p=i;
}
else if(i==0)
{
//for first word
for(k=i;k<p;k++)
{
//printf("%c",st[k]);
rst[++j]=st[k];
}
}
}
printf("Now reversing the sentence...\n");
puts(rst);
return 0;
}
Use a main for loop to traverse till the end of the sentence:
Copy the letters in a string until you find a space.
now call add#beginning function and in that function add the string each time you pass a string to the linked list.
print the contents of the linked list with a space inbetween to get the expected output
My code,just traverse from the last and if you find a space print the characters before it,now change the end to space-1;This will print till the second word,finally just print the first word using a single for loop.Comment for alter approach.
Program:
#include<stdio.h>
int main()
{
char str[200];
int i,j,k;
scanf("%[^\n]s",&str);
for(i=0;str[i]!='\0';i++);
i=i-1;
for(j=i;j>=0;j--)
{
if((str[j])==' ')
{
for(k=j+1;k<=i;k++)
{
printf("%c",str[k]);
}
i=j-1;
printf(" ");
}
}
for(k=0;k<=i;k++)
{
printf("%c",str[k]);
}
}
using stack
#include <iostream>
#include <stdio.h>
#include <stack>
int main()
{
std::stack<string> st;
char *words= "this is a test";
char * temp = (char *)calloc(1, sizeof(*temp));
int size1= strlen(words);
int k2=0;
int k3=0;
for(int i=0;i<=size1;i++)
{
temp[k2] = words[i];
k2++;
if(words[i] == ' ')
{
k3++;
if(k3==1)
temp[k2-1]='\0';
temp[k2]='\0';
st.push(temp);
k2=0;
}
if(words[i] == '\0')
{
temp[k2]='\0';
st.push(temp);
k2=0;
break;
}
}
while (!st.empty())
{
printf("%s",st.top().c_str());
st.pop();
}

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