Segmentation fault error

[gutty333]

Hello everyone I am having an odd problem, I currently finished a programming challenge from coderbyte. I used visual studio for testing and writing my code and than I copy it to their native environment on coderbyte. When I run the program on visual studio everything works fine and the solution is correct (at least with the test I have). Now when I transfer to coderbyte I am getting a segmentation error on the bool search function, any ideas what the issue might be?

I did some reading on the topic with regards to array/pointer with segmentation debugging and I looked back on my code and everything to me seems logical. here is the code.

  // Linear search function to check if a character is currently in that string
bool search(string temp, char letter)
{
	for (int x = 0; x < temp.length(); x++)
	{
		if (letter == temp[x])
		{
			return true;
		}
	}
	return false;
}

// Function that will determine how many unique characters are in the specified string
int uniqueCount(string temp)
{
	string uniqueString;

	for (int x = 0; x < temp.length(); x++)
	{
	    if ( x == 0 )
	    {
	        uniqueString.push_back(temp[x]);
	    }
		else if (!search(uniqueString, temp[x])) // Insert only the uniquer character into the string
		{
			uniqueString.push_back(temp[x]);
		}
	}
	return uniqueString.length(); // return the current total number of unique characters
}

string KUniqueCharacters(string str) {
	// getting the first character as an integer
	int unique = int(str[0]) - 48;

	int index = 1;
	string temp, temp2;

	while (index < str.length())
	{
		for (int x = index; x < str.length(); x++)
		{
			temp.push_back(str[x]);

			// Condition for when we reach pass the k integer
			// delete the last character for that substring
			if (uniqueCount(temp) > unique)
			{
				x--;
				temp.erase(temp.end());

				// Compare to keep the largest substring
				if (temp.length() > temp2.length())
				{
					temp2 = temp;
				}
				temp.clear();
			}
		}

		// We compare once more in the case that the substring continues to the end
		if (temp.length() > temp2.length())
		{
			temp2 = temp;
		}
		temp.clear();
		index++;
	}

	return temp2;
}

here is the exact error I am getting:
bash: line 7: 14231 Segmentation fault (core dumped) ./a.out
line 7 being line 3 in the code sample I posted

[coder777]

Line 51: temp.end() is not a valid iterator. See:

http://www.cplusplus.com/reference/string/string/erase/

An invalid p in (2), or an invalid range in (3), causes undefined behavior.

If you want to remove the last char use pop_back():

http://www.cplusplus.com/reference/string/string/pop_back/

[gutty333]

Yeah that was the other issued since pop_back correct me if I am wrong only works for C++ 11, the environment they use is an older version. In my ide I utilized the pop_back method though. Also thank you I used the temp.erase(temp.end()-1) and it works as intended.

I thought the temp.end() signified the last character. the same way temp.begin() signifies the beginning character correct?

EDIT:
Ok never mind it seems the end() returns an index/iterator past the last element of a string. Wich makes sense now for the segmentation error I was getting. Again thank you