While loop not seeing or finding terminating null character - c++

Question

I am trying to iterate through a char array using a while loop using '\0' as the terminating condition, but my problem is that its not finding the '\0' until index position 481, the array is declared as 200 long and I cant see what I am doing wrong!! I cannot use strings or any form of string functions for this before anyone asks. Can anyone help??
#include <iostream>
using namespace std;
int main()
{
char fullString[200]={'\0'}; // Declare char string of 200, containing null characters
int alphaCount = 0;
int charCount = 0;
int wordCount = 0;
cin.getline(fullString,200); //
cout << "\n\n" << fullString;
cout << "\n\n\n";
int i=0;
int i2 = 0;
while(fullString[i]!='\0'){ //iterate through array until NULL character is found
cout << "\n\nIndex pos : " << fullString[i]; //Output char at 'i' position
while(fullString[i2]!= ' '){ //while 'i' is not equal to SPACE, iterate4 through array
if(isalpha(fullString[i2])){
alphaCount++; // count if alpha character at 'i'
}
charCount++; // count all chars at 'i'
i2++;
}
if(charCount == alphaCount){ // if charCount and alphaCount are equal, word is valid
wordCount++;
}
charCount = 0; // zero charCount and alphaCount
alphaCount = 0;
i=i2;// Assign the position of 'i2' to 'i'
while(fullString[i] == 32){ //if spaces are present, iterate past them
i++;
cout << "\n\ntest1";
}
i2 = i; // assign value of 'i' to 'i2' which is the next position of a character in the array
if(fullString[i] == '\0')
{
cout << "\n\nNull Character " << endl;
cout << "found at pos: " << i << endl;
}
}
cout << "\n\ni" << i;
cout << "\n\nWord" << wordCount;
return 0;
}

Answer 1

As others have pointed out, your problem is with the inner loop. You test for a space character but not for NULL, so it's iterating past the end of the last word because there is no space character after the last word.
This is easily fixed by changing your while condition from this:
while(fullString[i2]!= ' ')
... to this:
while(fullString[i2] && fullString[i2]!= ' ')
This will change your inner while loop to first test for non-NULL, and then test for non-space.
I'm not correcting the rest of your code because I presume this is a class project (it looks like one) so I'm limiting my answer to the scope of your question.

Answer 2

You do not check in the inner loop
while(fullString[i2]!= ' '){ //while 'i' is not equal to SPACE, iterate4 through array
if(isalpha(fullString[i2])){
alphaCount++; // count if alpha character at 'i'
}
charCount++; // count all chars at 'i'
i2++;
}
...
i=i2;// Assign the position of 'i2' to 'i'
whether the next character is equal to '\0'

Answer 3

It's because the inner loops don't check for the termination, they just continue looping even past the end of the string.
By the way, if you want to count the number of words, spaces and non-space characters, there are easier ways in C++. See e.g. std::count and std::count_if for the spaces and characters. For example:
std::string input = "Some string\twith multiple\nspaces in it.";
int num_spaces = std::count_if(std::begin(input), std::end(input),
[](const char& ch){ return std::isspace(ch); });
For counting words, you can use std::istringstream, std::vector, std::copy, std::istream_iterator and std::back_inserter:
std::istringstream iss(input);
std::vector<std::string> words;
std::copy(std::istream_iterator<std::string>(iss),
std::istream_iterator<std::string>(),
std::back_inserter(words));
After the code above, the size of the words vector is the number of words.
If you use e.g. std::copy_if then you can use the above code for the other cases as well (but std::count_if is better for single character classes).