Split char array in 'C' to CSV's - c

I need to split a char array into CSV's. Actually we can do the reverse of it using strtok() like:
#include <stdio.h>
#include <string.h>
int main ()
{
char str[] ="This,a,sample,string.";
char * pch;
printf ("Splitting string \"%s\" into tokens:\n",str);
pch = strtok (str,",");
while (pch != NULL)
{
printf ("%s\n",pch);
pch = strtok (NULL, ",");
}
return 0;
}
But in my case, there's an char array suppose char bits[1024]="abcdefghijklmn". I need to get the output as a,b,c,d,e,f,g,h,i,j,k,m,n.
Is there any function or library to do this i.e. in terms of raw meaning, for every character it has to put a comma.

Just iterate over the string until you hit the end-of-string '\0' character. Or use the length of the data in the array (which may be smaller than the array size) and use a simple for loop.

This works for a null terminated string. But it will leave a dangling comma at the end.
void tokenise(char *s, char *d)
{
while(*d++ = *s++) *d++ = ',';
}
If you know the length of the string already, you can pass that through. This will not leave a dangling comma.
void tokenise(char *s, char *d, int length)
{
int i = 0;
while((*d++ = *s++) && ((i++)<(length-1))) *d++ = ',';
}
In both examples, s is a pointer to the source string and d points to the output tokenised string. It is up to the calling code to ensure the buffer d points to is sufficiently large.

you can use this simple function from old basic :
// ............................................................. string word at
char * word_at(char *tString, int upTo, char *dilim) {
int wcount;
char *rString, *temp;
temp= (char *) malloc(sizeof(char) * (strlen(tString)+1));
strcpy(temp, tString);
rString= strtok(temp, dilim);
wcount=1;
while (rString != NULL){
if (wcount==upTo) {
return rString;
}
rString= strtok(NULL, dilim);
wcount++;
}
return tString ;
}
parameter : string , index and character delimiter
return : word : ( char *)

If you find easy to implement it, then this could help you to start
char* split_all( char arr[], char ch )
{
char *new, *ptr;
new = ptr = calloc( 1, 2*strlen( arr ) ); // FIXME : Error checks
for( ; *(arr + 1) ; new++, arr++ )
{
*new = *arr;
new++;
*new = ch;
}
*new = *arr;
return ptr;
}
You can re-use, optimize this for your requirement. Its a quick and dirty solution, feel free to fix it..

Related

Searching an array for a specific character [duplicate]

I want to write a program in C that displays each word of a whole sentence (taken as input) at a seperate line. This is what I have done so far:
void manipulate(char *buffer);
int get_words(char *buffer);
int main(){
char buff[100];
printf("sizeof %d\nstrlen %d\n", sizeof(buff), strlen(buff)); // Debugging reasons
bzero(buff, sizeof(buff));
printf("Give me the text:\n");
fgets(buff, sizeof(buff), stdin);
manipulate(buff);
return 0;
}
int get_words(char *buffer){ // Function that gets the word count, by counting the spaces.
int count;
int wordcount = 0;
char ch;
for (count = 0; count < strlen(buffer); count ++){
ch = buffer[count];
if((isblank(ch)) || (buffer[count] == '\0')){ // if the character is blank, or null byte add 1 to the wordcounter
wordcount += 1;
}
}
printf("%d\n\n", wordcount);
return wordcount;
}
void manipulate(char *buffer){
int words = get_words(buffer);
char *newbuff[words];
char *ptr;
int count = 0;
int count2 = 0;
char ch = '\n';
ptr = buffer;
bzero(newbuff, sizeof(newbuff));
for (count = 0; count < 100; count ++){
ch = buffer[count];
if (isblank(ch) || buffer[count] == '\0'){
buffer[count] = '\0';
if((newbuff[count2] = (char *)malloc(strlen(buffer))) == NULL) {
printf("MALLOC ERROR!\n");
exit(-1);
}
strcpy(newbuff[count2], ptr);
printf("\n%s\n",newbuff[count2]);
ptr = &buffer[count + 1];
count2 ++;
}
}
}
Although the output is what I want, I have really many black spaces after the final word displayed, and the malloc() returns NULL so the MALLOC ERROR! is displayed in the end.
I can understand that there is a mistake at my malloc() implementation, but I do not know what it is.
Is there another more elegant or generally better way to do it?
http://www.cplusplus.com/reference/clibrary/cstring/strtok/
Take a look at this, and use whitespace characters as the delimiter. If you need more hints let me know.
From the website:
char * strtok ( char * str, const char * delimiters );
On a first call, the function expects a C string as argument for str, whose first character is used as the starting location to scan for tokens. In subsequent calls, the function expects a null pointer and uses the position right after the end of last token as the new starting location for scanning.
Once the terminating null character of str is found in a call to strtok, all subsequent calls to this function (with a null pointer as the first argument) return a null pointer.
Parameters
str
C string to truncate.
Notice that this string is modified by being broken into smaller strings (tokens).
Alternativelly [sic], a null pointer may be specified, in which case the function continues scanning where a previous successful call to the function ended.
delimiters
C string containing the delimiter characters.
These may vary from one call to another.
Return Value
A pointer to the last token found in string.
A null pointer is returned if there are no tokens left to retrieve.
Example
/* strtok example */
#include <stdio.h>
#include <string.h>
int main ()
{
char str[] ="- This, a sample string.";
char * pch;
printf ("Splitting string \"%s\" into tokens:\n",str);
pch = strtok (str," ,.-");
while (pch != NULL)
{
printf ("%s\n",pch);
pch = strtok (NULL, " ,.-");
}
return 0;
}
For the fun of it here's an implementation based on the callback approach:
const char* find(const char* s,
const char* e,
int (*pred)(char))
{
while( s != e && !pred(*s) ) ++s;
return s;
}
void split_on_ws(const char* s,
const char* e,
void (*callback)(const char*, const char*))
{
const char* p = s;
while( s != e ) {
s = find(s, e, isspace);
callback(p, s);
p = s = find(s, e, isnotspace);
}
}
void handle_word(const char* s, const char* e)
{
// handle the word that starts at s and ends at e
}
int main()
{
split_on_ws(some_str, some_str + strlen(some_str), handle_word);
}
malloc(0) may (optionally) return NULL, depending on the implementation. Do you realize why you may be calling malloc(0)? Or more precisely, do you see where you are reading and writing beyond the size of your arrays?
Consider using strtok_r, as others have suggested, or something like:
void printWords(const char *string) {
// Make a local copy of the string that we can manipulate.
char * const copy = strdup(string);
char *space = copy;
// Find the next space in the string, and replace it with a newline.
while (space = strchr(space,' ')) *space = '\n';
// There are no more spaces in the string; print out our modified copy.
printf("%s\n", copy);
// Free our local copy
free(copy);
}
Something going wrong is get_words() always returning one less than the actual word count, so eventually you attempt to:
char *newbuff[words]; /* Words is one less than the actual number,
so this is declared to be too small. */
newbuff[count2] = (char *)malloc(strlen(buffer))
count2, eventually, is always one more than the number of elements you've declared for newbuff[]. Why malloc() isn't returning a valid ptr, though, I don't know.
You should be malloc'ing strlen(ptr), not strlen(buf). Also, your count2 should be limited to the number of words. When you get to the end of your string, you continue going over the zeros in your buffer and adding zero size strings to your array.
Just as an idea of a different style of string manipulation in C, here's an example which does not modify the source string, and does not use malloc. To find spaces I use the libc function strpbrk.
int print_words(const char *string, FILE *f)
{
static const char space_characters[] = " \t";
const char *next_space;
// Find the next space in the string
//
while ((next_space = strpbrk(string, space_characters)))
{
const char *p;
// If there are non-space characters between what we found
// and what we started from, print them.
//
if (next_space != string)
{
for (p=string; p<next_space; p++)
{
if(fputc(*p, f) == EOF)
{
return -1;
}
}
// Print a newline
//
if (fputc('\n', f) == EOF)
{
return -1;
}
}
// Advance next_space until we hit a non-space character
//
while (*next_space && strchr(space_characters, *next_space))
{
next_space++;
}
// Advance the string
//
string = next_space;
}
// Handle the case where there are no spaces left in the string
//
if (*string)
{
if (fprintf(f, "%s\n", string) < 0)
{
return -1;
}
}
return 0;
}
you can scan the char array looking for the token if you found it just print new line else print the char.
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
int main()
{
char *s;
s = malloc(1024 * sizeof(char));
scanf("%[^\n]", s);
s = realloc(s, strlen(s) + 1);
int len = strlen(s);
char delim =' ';
for(int i = 0; i < len; i++) {
if(s[i] == delim) {
printf("\n");
}
else {
printf("%c", s[i]);
}
}
free(s);
return 0;
}
char arr[50];
gets(arr);
int c=0,i,l;
l=strlen(arr);
for(i=0;i<l;i++){
if(arr[i]==32){
printf("\n");
}
else
printf("%c",arr[i]);
}

String and String array Manipulation in c

I'm trying to write a string spliter function in C.It uses space as delimiter to split a given string in two or more. It more like the split funtion in Python.Here is the code:-
#include <stdio.h>
#include <string.h>
void slice_input (char *t,char **out)
{
char *x,temp[10];
int i,j;
x = t;
j=0;
i=0;
for (;*x!='\0';x++){
if (*x!=' '){
temp[i] = *x;
i++;
}else if(*x==' '){
out[j] = temp;
j++;i=0;
}
}
}
int main()
{
char *out[2];
char inp[] = "HEllo World ";
slice_input(inp,out);
printf("%s\n%s",out[0],out[1]);
//printf("%d",strlen(out[1]));
return 0;
}
Expeted Output:-
HEllo
World
but it is showing :-
World
World
Can you help please?
out[j] = temp;
where temp is a local variable. It will go out of scope as soon as your function terminates, thus out[j] will point to garbage, invoking Undefined Behavior when being accessed.
A simple fix would be to use a 2D array for out, and use strcpy() to copy the temp string to out[j], like this:
#include <stdio.h>
#include <string.h>
void slice_input(char *t, char out[2][10]) {
char *x, temp[10];
int i,j;
x = t;
j=0;
i=0;
for (;*x!='\0';x++) {
if (*x!=' ') {
temp[i] = *x;
i++;
} else if(*x==' ') {
strcpy(out[j], temp);
j++;
i=0;
}
}
}
int main()
{
char out[2][10];
char inp[] = "HEllo World ";
slice_input(inp,out);
printf("%s\n%s",out[0],out[1]);
return 0;
}
Output:
HEllo
World
http://www.cplusplus.com/reference/clibrary/cstring/strtok/
From the website:
char * strtok ( char * str, const char * delimiters ); On a first
call, the function expects a C string as argument for str, whose first
character is used as the starting location to scan for tokens. In
subsequent calls, the function expects a null pointer and uses the
position right after the end of last token as the new starting
location for scanning.
Once the terminating null character of str is found in a call to
strtok, all subsequent calls to this function (with a null pointer as
the first argument) return a null pointer.
Parameters
str C string to truncate. Notice that this string is modified by being
broken into smaller strings (tokens). Alternativelly [sic], a null
pointer may be specified, in which case the function continues
scanning where a previous successful call to the function ended.
delimiters C string containing the delimiter characters. These may
vary from one call to another. Return Value
A pointer to the last token found in string. A null pointer is
returned if there are no tokens left to retrieve.
Example
/* strtok example */
#include <stdio.h>
#include <string.h>
int main ()
{
char str[] ="- This, a sample string.";
char * pch;
printf ("Splitting string \"%s\" into tokens:\n",str);
pch = strtok (str," ,.-");
while (pch != NULL)
{
printf ("%s\n",pch);
pch = strtok (NULL, " ,.-");
}
return 0;
}
You can use this function to split string into tokens - there is no need to use some own functions. Your code looks like garbage, please format it.
Your source propably would look like this:
char *
strtok(s, delim)
char *s; /* string to search for tokens */
const char *delim; /* delimiting characters */
{
static char *lasts;
register int ch;
if (s == 0)
s = lasts;
do {
if ((ch = *s++) == '\0')
return 0;
} while (strchr(delim, ch));
--s;
lasts = s + strcspn(s, delim);
if (*lasts != 0)
*lasts++ = 0;
return s;
}

scanning from an input file in C until reaching a certain character (#)?

Simple question:
If i have a line in an input file that looks looks like:
Hello#Great#Day#Today
how can I scan in each word individually as its own array, in other words tell C to stop scanning when it reaches the # character and then go in the next iteration of the loop to scan the next word as a separate array?
This is assuming you are reading through stdin. Definitely take a look at #Whoz kick start approach as well (very similar to this).
What you would want to do is create a dynamic array and populate it with every byte read through stdin. You would then want to create an array of character pointers that will point to the first character in every "word", where you define a word as every character before a '#' character (delimiter). You would then iterate through that array of characters and populate the array of character pointers with the memory addresses of the first character in each word.
Use strtok() to tokenize your input by the specified character.
http://www.cplusplus.com/reference/cstring/strtok/
char str[] ="- This, a sample string.";
char * pch;
printf ("Splitting string \"%s\" into tokens:\n",str);
pch = strtok (str,"#");
while (pch != NULL)
{
printf ("%s\n",pch);
pch = strtok (NULL, "#");
}
In two stages, I have used something like this:
#include <ansi_c.h>
//tokenizing a string
int GetCount(char *in, char *delim, int *m);
int GetStrings(char *in, char *delim, int count, char **out);
void main(void)
{
int count, maxlen, i;
char inpString[]={"Hello#Greatest#Day#Today"};
char *resultBuf[10];
//get a count of strings to store
count = GetCount(inpString, "#", &maxlen);
for(i=0;i<10;i++)
{
resultBuf[i] = calloc(maxlen+1, sizeof(char));
}
//Store strings in arrays
GetStrings(inpString, "#", count, resultBuf);
for(i=0;i<count;i++)
{
printf("%s\n", resultBuf[i]);
free(resultBuf[i];
}
}
//Gets count of tokens (delimited strings)
int GetCount(char *in, char *delim, int *m)
{
char *buf=0;
char temp1[10]={0};
char *inStr;
int count = 0;
int max = 0, keepMax = 0;
if(in)
{
inStr = calloc(strlen(in)+1, sizeof(char));
strcpy(inStr, in);
if(strlen(inStr) > 1)
{
count = 0;
buf = strtok(inStr, delim);
while(buf)
{
strcpy(temp1, buf);
max = strlen(temp1);
(max > keepMax)?(keepMax = max):(keepMax == keepMax);
count++;
buf = strtok(NULL, delim);
}
*m = keepMax;
}
free(inStr);
}
return count;
}
//Gets array of strings
int GetStrings(char *in, char *delim, int count, char **out)
{
char *buf=0;
char *inStr;
int i = 0;
if(in)
{
inStr = calloc(strlen(in)+1, sizeof(char));
strcpy(inStr, in);
if(strlen(inStr) > 1)
{
buf = strtok(inStr, delim);
while(buf)
{
strcpy(out[i], buf);
buf = strtok(NULL, delim);
i++;
}
}
free(inStr);
}
return 0;
}

Split string in C every white space

I want to write a program in C that displays each word of a whole sentence (taken as input) at a seperate line. This is what I have done so far:
void manipulate(char *buffer);
int get_words(char *buffer);
int main(){
char buff[100];
printf("sizeof %d\nstrlen %d\n", sizeof(buff), strlen(buff)); // Debugging reasons
bzero(buff, sizeof(buff));
printf("Give me the text:\n");
fgets(buff, sizeof(buff), stdin);
manipulate(buff);
return 0;
}
int get_words(char *buffer){ // Function that gets the word count, by counting the spaces.
int count;
int wordcount = 0;
char ch;
for (count = 0; count < strlen(buffer); count ++){
ch = buffer[count];
if((isblank(ch)) || (buffer[count] == '\0')){ // if the character is blank, or null byte add 1 to the wordcounter
wordcount += 1;
}
}
printf("%d\n\n", wordcount);
return wordcount;
}
void manipulate(char *buffer){
int words = get_words(buffer);
char *newbuff[words];
char *ptr;
int count = 0;
int count2 = 0;
char ch = '\n';
ptr = buffer;
bzero(newbuff, sizeof(newbuff));
for (count = 0; count < 100; count ++){
ch = buffer[count];
if (isblank(ch) || buffer[count] == '\0'){
buffer[count] = '\0';
if((newbuff[count2] = (char *)malloc(strlen(buffer))) == NULL) {
printf("MALLOC ERROR!\n");
exit(-1);
}
strcpy(newbuff[count2], ptr);
printf("\n%s\n",newbuff[count2]);
ptr = &buffer[count + 1];
count2 ++;
}
}
}
Although the output is what I want, I have really many black spaces after the final word displayed, and the malloc() returns NULL so the MALLOC ERROR! is displayed in the end.
I can understand that there is a mistake at my malloc() implementation, but I do not know what it is.
Is there another more elegant or generally better way to do it?
http://www.cplusplus.com/reference/clibrary/cstring/strtok/
Take a look at this, and use whitespace characters as the delimiter. If you need more hints let me know.
From the website:
char * strtok ( char * str, const char * delimiters );
On a first call, the function expects a C string as argument for str, whose first character is used as the starting location to scan for tokens. In subsequent calls, the function expects a null pointer and uses the position right after the end of last token as the new starting location for scanning.
Once the terminating null character of str is found in a call to strtok, all subsequent calls to this function (with a null pointer as the first argument) return a null pointer.
Parameters
str
C string to truncate.
Notice that this string is modified by being broken into smaller strings (tokens).
Alternativelly [sic], a null pointer may be specified, in which case the function continues scanning where a previous successful call to the function ended.
delimiters
C string containing the delimiter characters.
These may vary from one call to another.
Return Value
A pointer to the last token found in string.
A null pointer is returned if there are no tokens left to retrieve.
Example
/* strtok example */
#include <stdio.h>
#include <string.h>
int main ()
{
char str[] ="- This, a sample string.";
char * pch;
printf ("Splitting string \"%s\" into tokens:\n",str);
pch = strtok (str," ,.-");
while (pch != NULL)
{
printf ("%s\n",pch);
pch = strtok (NULL, " ,.-");
}
return 0;
}
For the fun of it here's an implementation based on the callback approach:
const char* find(const char* s,
const char* e,
int (*pred)(char))
{
while( s != e && !pred(*s) ) ++s;
return s;
}
void split_on_ws(const char* s,
const char* e,
void (*callback)(const char*, const char*))
{
const char* p = s;
while( s != e ) {
s = find(s, e, isspace);
callback(p, s);
p = s = find(s, e, isnotspace);
}
}
void handle_word(const char* s, const char* e)
{
// handle the word that starts at s and ends at e
}
int main()
{
split_on_ws(some_str, some_str + strlen(some_str), handle_word);
}
malloc(0) may (optionally) return NULL, depending on the implementation. Do you realize why you may be calling malloc(0)? Or more precisely, do you see where you are reading and writing beyond the size of your arrays?
Consider using strtok_r, as others have suggested, or something like:
void printWords(const char *string) {
// Make a local copy of the string that we can manipulate.
char * const copy = strdup(string);
char *space = copy;
// Find the next space in the string, and replace it with a newline.
while (space = strchr(space,' ')) *space = '\n';
// There are no more spaces in the string; print out our modified copy.
printf("%s\n", copy);
// Free our local copy
free(copy);
}
Something going wrong is get_words() always returning one less than the actual word count, so eventually you attempt to:
char *newbuff[words]; /* Words is one less than the actual number,
so this is declared to be too small. */
newbuff[count2] = (char *)malloc(strlen(buffer))
count2, eventually, is always one more than the number of elements you've declared for newbuff[]. Why malloc() isn't returning a valid ptr, though, I don't know.
You should be malloc'ing strlen(ptr), not strlen(buf). Also, your count2 should be limited to the number of words. When you get to the end of your string, you continue going over the zeros in your buffer and adding zero size strings to your array.
Just as an idea of a different style of string manipulation in C, here's an example which does not modify the source string, and does not use malloc. To find spaces I use the libc function strpbrk.
int print_words(const char *string, FILE *f)
{
static const char space_characters[] = " \t";
const char *next_space;
// Find the next space in the string
//
while ((next_space = strpbrk(string, space_characters)))
{
const char *p;
// If there are non-space characters between what we found
// and what we started from, print them.
//
if (next_space != string)
{
for (p=string; p<next_space; p++)
{
if(fputc(*p, f) == EOF)
{
return -1;
}
}
// Print a newline
//
if (fputc('\n', f) == EOF)
{
return -1;
}
}
// Advance next_space until we hit a non-space character
//
while (*next_space && strchr(space_characters, *next_space))
{
next_space++;
}
// Advance the string
//
string = next_space;
}
// Handle the case where there are no spaces left in the string
//
if (*string)
{
if (fprintf(f, "%s\n", string) < 0)
{
return -1;
}
}
return 0;
}
you can scan the char array looking for the token if you found it just print new line else print the char.
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
int main()
{
char *s;
s = malloc(1024 * sizeof(char));
scanf("%[^\n]", s);
s = realloc(s, strlen(s) + 1);
int len = strlen(s);
char delim =' ';
for(int i = 0; i < len; i++) {
if(s[i] == delim) {
printf("\n");
}
else {
printf("%c", s[i]);
}
}
free(s);
return 0;
}
char arr[50];
gets(arr);
int c=0,i,l;
l=strlen(arr);
for(i=0;i<l;i++){
if(arr[i]==32){
printf("\n");
}
else
printf("%c",arr[i]);
}

How to remove \n or \t from a given string in C?

How can I strip a string with all \n and \t in C?
This works in my quick and dirty tests. Does it in place:
#include <stdio.h>
void strip(char *s) {
char *p2 = s;
while(*s != '\0') {
if(*s != '\t' && *s != '\n') {
*p2++ = *s++;
} else {
++s;
}
}
*p2 = '\0';
}
int main() {
char buf[] = "this\t is\n a\t test\n test";
strip(buf);
printf("%s\n", buf);
}
And to appease Chris, here is a version which will make a place the result in a newly malloced buffer and return it (thus it'll work on literals). You will need to free the result.
char *strip_copy(const char *s) {
char *p = malloc(strlen(s) + 1);
if(p) {
char *p2 = p;
while(*s != '\0') {
if(*s != '\t' && *s != '\n') {
*p2++ = *s++;
} else {
++s;
}
}
*p2 = '\0';
}
return p;
}
If you want to replace \n or \t with something else, you can use the function strstr(). It returns a pointer to the first place in a function that has a certain string. For example:
// Find the first "\n".
char new_char = 't';
char* pFirstN = strstr(szMyString, "\n");
*pFirstN = new_char;
You can run that in a loop to find all \n's and \t's.
If you want to "strip" them, i.e. remove them from the string, you'll need to actually use the same method as above, but copy the contents of the string "back" every time you find a \n or \t, so that "this i\ns a test" becomes: "this is a test".
You can do that with memmove (not memcpy, since the src and dst are pointing to overlapping memory), like so:
char* temp = strstr(str, "\t");
// Remove \n.
while ((temp = strstr(str, "\n")) != NULL) {
// Len is the length of the string, from the ampersand \n, including the \n.
int len = strlen(str);
memmove(temp, temp + 1, len);
}
You'll need to repeat this loop again to remove the \t's.
Note: Both of these methods work in-place. This might not be safe! (read Evan Teran's comments for details.. Also, these methods are not very efficient, although they do utilize a library function for some of the code instead of rolling your own.
Basically, you have two ways to do this: you can create a copy of the original string, minus all '\t' and '\n' characters, or you can strip the string "in-place." However, I bet money that the first option will be faster, and I promise you it will be safer.
So we'll make a function:
char *strip(const char *str, const char *d);
We want to use strlen() and malloc() to allocate a new char * buffer the same size as our str buffer. Then we go through str character by character. If the character is not contained in d, we copy it into our new buffer. We can use something like strchr() to see if each character is in the string d. Once we're done, we have a new buffer, with the contents of our old buffer minus characters in the string d, so we just return that. I won't give you sample code, because this might be homework, but here's the sample usage to show you how it solves your problem:
char *string = "some\n text\t to strip";
char *stripped = strip(string, "\t\n");
This is a c string function that will find any character in accept and return a pointer to that position or NULL if it is not found.
#include <string.h>
char *strpbrk(const char *s, const char *accept);
Example:
char search[] = "a string with \t and \n";
char *first_occ = strpbrk( search, "\t\n" );
first_occ will point to the \t, or the 15 character in search. You can replace then call again to loop through until all have been replaced.
I like to make the standard library do as much of the work as possible, so I would use something similar to Evan's solution but with strspn() and strcspn().
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#define SPACE " \t\r\n"
static void strip(char *s);
static char *strip_copy(char const *s);
int main(int ac, char **av)
{
char s[] = "this\t is\n a\t test\n test";
char *s1 = strip_copy(s);
strip(s);
printf("%s\n%s\n", s, s1);
return 0;
}
static void strip(char *s)
{
char *p = s;
int n;
while (*s)
{
n = strcspn(s, SPACE);
strncpy(p, s, n);
p += n;
s += n + strspn(s+n, SPACE);
}
*p = 0;
}
static char *strip_copy(char const *s)
{
char *buf = malloc(1 + strlen(s));
if (buf)
{
char *p = buf;
char const *q;
int n;
for (q = s; *q; q += n + strspn(q+n, SPACE))
{
n = strcspn(q, SPACE);
strncpy(p, q, n);
p += n;
}
*p++ = '\0';
buf = realloc(buf, p - buf);
}
return buf;
}

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