Thread: how to break a string into array of strings

i have a string in which words are separated by space

i want to create an array of strings ,each string contains a word
from the original string

i tried like this.
but the debugger doesnt show me the stucture
i just says bad ptr

i cant see why its not breaking into peaces
??

Code:

#include <stdio.h>
#include <string.h>
#include <stdlib.h>

typedef struct node node;
struct node{
	int value;
	struct node * next;
};
 int countletters(char *str);
 char * sortbycount(char* str);
void main()
{
	int g;
	char  str[18]="aabx bXcb bBxaDAa";
	char * r;
	g=countletters(str);
	r=sortbycount(str);
}


int countletters(char *str)
{
	int i,cnt=0;
	int ch[26]={0};
    for (i=0;i<(int)strlen(str);i++)
	{
       if ((str[i]>='a')&&(str[i]<='z'))
	   {
          ch[str[i]-'a']=1;
	   }
	   if ((str[i]>='A')&&(str[i]<='Z'))
	   {
          ch[str[i]-'A']=1;
	   }
	}
	for (i=0;i<26;i++)
	{
		if(ch[i]==1){ cnt++;}
	}
	printf("%d",cnt);
   return cnt;
}

char * sortbycount(char* str)
{
  int start=0,i,cnt=0;char** arr;
  for (i=0;i<(int)strlen(str);i++)
  {
    if (str[i]==' ') cnt++;
  }
  arr=(char**)malloc(sizeof(char*)*cnt);
  i=0;
  do
  {
     for (i=start;str[i]!=' ';i++);
     arr[i]=(char*)malloc(sizeof(char)*(i-start));
     sprintf(arr[i],"%s",str+i); 
	 start=i;

  }while(i<cnt);
  
 return str;
}

Is there a reason you're not using strtok? It would make this a whole lot easier - you just pass it a string and a delimiter (' ', in this case), and each subsequent call will return a pointer to the next word...

I suspect you wrote this program all at once and then tried compiling it - have you tried writing the program in small pieces and testing it at each stage? It's a lot easier to debug one small function than a whole program. Also, if you post an error, tell us what line the error occurs on.

Also using (int)strlen(str) for the condition of a loop statement is also unwise, it forces the program to do this calculation on each pass of the loop.. increasing the processing resources/time required for the program to finish its job. I would suggest using an int variable holding the value of (int)strlen(str) and then using this value in the condition of the loop. This way that one calculation is only completed once, but still as functional for the overall design with an increase in performance.

Code:

int len=(int)strlen(str);
for( i=0 ; i < len ; i++ ) {
    // do some processing here
}

I'm not sure though, but what is the purpose of counting the letters? It seems to serve no purpose other then to output the total number of separate (not including repeats) characters found within the string. This doesn't seem to have a purpose in terms of separating a string into various smaller array blocks, but I do agree that strtok would do this program a lot of justice.

i am not alowed to use strtok

i am counting the spaces and the number of words is the number of spaces+1

use getc to read in one character at a time
while the character is not a space
append the character to the current array index
when you hit a space
increment the index
repeat

thats what i did in sprintf
it should stop copying when it gets a space
because its %s

thats what i did in sprintf
it should stop copying when it gets a space
because its %s

Have you, by any chance, tested to see if that's what it's doing? %s reads a string, not a word.

i know
it should stop copying when it gets a space
because its %s
but in this fixed
it copies the whole thing
??

Code:

#include <stdio.h>
#include <string.h>
#include <stdlib.h>

typedef struct node node;
struct node{
	int value;
	struct node * next;
};
 int countletters(char *str);
 char * sortbycount(char* str);
void main()
{
	int g;
	char  str[18]="aabx bXcb bBxaDAa";
	char * r;
	g=countletters(str);
	r=sortbycount(str);
}


int countletters(char *str)
{
	int i,cnt=0;
	int ch[26]={0};
    for (i=0;i<(int)strlen(str);i++)
	{
       if ((str[i]>='a')&&(str[i]<='z'))
	   {
          ch[str[i]-'a']=1;
	   }
	   if ((str[i]>='A')&&(str[i]<='Z'))
	   {
          ch[str[i]-'A']=1;
	   }
	}
	for (i=0;i<26;i++)
	{
		if(ch[i]==1){ cnt++;}
	}
	printf("%d",cnt);
   return cnt;
}

char * sortbycount(char* str)
{
  int start=0,t=0,i,cnt=0;char** arr;
  for (i=0;i<(int)strlen(str);i++)
  {
    if (str[i]==' ') cnt++;
  }
  arr=(char**)malloc(sizeof(char*)*(cnt+1));
  i=0;
  do
  {
     for (i=start;str[i]!=' ';i++);
     arr[t]=(char*)malloc(sizeof(char)*(i-start));
     sprintf(arr[t],"%s",str+start); 
	 start=i;
   t++;
  }while(t<cnt);
  
 return str;
}

>> void main()

Again, wrong, wrong, wrong.
========================
it compiles so its fine by me.


>> char** arr;

Wouldn't it be a good idea to return it's value? And free( ) it when you're done with it, for that matter?
=======================
an array of strings is **


>> if (str[i]==' ') cnt++;

That doesn't count words, but spaces.
===============================
the number of words is the number of spaces +1


>> sprintf(arr[t],"%s",str+start);

sprintf isn't going to help you here.
==============================
this sentence doesnt give any information.
i explained why it should work in previos threads
you said "isnt going to help"
very helpfull

this sentence doesnt give any information.

I have never, not once, seen you ask a question, AND provide the appropriate information along with that question. You never tell us what you've tried, you never give us detailed errors, etc...

Furthermore, I already told you very clearly why your sprintf statement isn't going to work. You keep saying "it should" do this, but I just looked in the documentation, and "it should" read a string, not a word. Strings end with null characters, not with spaces. Why on earth should someone else give you more information, if you have 1500 posts proving that you don't learn from what other people have told you?

it compiles so its fine by me.

Your problem is that you don't want to learn. The reason you have been posting so long and still can't compile a simple program, is because you don't listen to what anyone tells you. You've never changed the way you ask questions, you've never thought through a problem yourself.

If you want people to help you - use int main(), because if you use void main(), odds are that they're going to have to edit your program before it will compile for them. Do yourself a favor and use int main().

i explained why it should work in previos threads

That's our whole point. You "THINK" things should work, but in reality, they don't. Stop making so many assumptions, and try things. Write a small part of the program, test it. Does it REALLY do what you think it's doing? If so, move on. If not, try and debug that small part of the program.


I don't mean to sound rude, so please don't take this as a flaming - but everyone on this board is here to help other people, and clearly, you have not been helped by the hundreds of other posts. Please start listening to the advice people give you, otherwise you are never going to learn anything meaningful.

ok so how to do so it will copy into arr[t] till str reaches a space
?