Count # of indexes in an array

Projects Programming
1

So lets say I have a string called rawinput = "Hi. This is raw input data." and make each word an element in an array. How would I do this assuming I didn't know or tell the program how many words are in the string. Is it possible to do this?

2

Hello,

sizeof(array)/sizeof(array[0])

Will give you the number of elements in an array. Not sure if that's what you asked :stuck_out_tongue:

3

If you want to know how many words are in a NULL terminated array of chars, you need to first define what a word is. If it is a collection of contiguous letters, separated by spaces. then all you need to do is count the spaces. assuming that only one space is used as a separator. Things get more challenging
if there can

be more than one space

or other kinds

of white space.

4

you cant have a dynamic array in C you want M for that, nice n easy self sorting sparse arrays, but you wont find an M compatable arduino or similar boards tho.

if its a case of finding out how many nodes of a 2d char array are populated, just ensure the last entry is always a null and count in a loop till null for your answer.

5

If the OP uses pointers then he can use strlen()

6

roboticfan101:
So lets say I have a string called rawinput = "Hi. This is raw input data." and make each word an element in an array. How would I do this assuming I didn't know or tell the program how many words are in the string. Is it possible to do this?

yes very well possible,

find below a wordCount sketch, it scans a string and keeps state if it is inside a word or not. You can extend this code to copy the characters to an element of a string array, where the index is defined by the wordcount so far. You can also change the definition of a word

//
//    FILE: wordCount.ino
//  AUTHOR: Rob Tillaart
// VERSION: 0.1.00
// PURPOSE: demo
//    DATE: 2014-11-09
//     URL:
//
// Released to the public domain
//

void setup() 
{
  Serial.begin(115200);
  Serial.println("Start ");

  Serial.println("Hi. This is raw input data.");
  Serial.println(wordCount("Hi. This is raw input data."));

  Serial.println("");
  Serial.println(wordCount(""));

  Serial.println("qwerty");
  Serial.println(wordCount("qwerty"));

  Serial.println(",./;'[]\\-=");
  Serial.println(wordCount(",./;'[]\\-="));

  Serial.println("temp\t123\tape");
  Serial.println(wordCount("temp\t123\tape"));

  Serial.println("temp\t 123\nape");
  Serial.println(wordCount("temp\t 123\nape"));

  Serial.println("aaa3bbb3");
  Serial.println(wordCount("aaa3bbb3"));
}

int wordCount(char* s)
{
  int words = 0;
  bool inword = false;

  for (int i=0; i<strlen(s); i++)
  {
    switch(s[i])
    {
    case 'a'...'z': 
    case 'A'...'Z':
      if (inword == false)
      {
        inword = true;
        words++;
      }
      break;
    default:
      inword = false;
    }
  }
  return words;
}

void loop() {}
7

Use the function strtok() to split up your long string.

...R

8

Things get more challenging
if there can

be more than one space

or other kinds

of white space.

Challenging, aye.