How can I split a string into multiple parts? I currently gather a string via bluetooth to my arduino and the string only has 5 different letters. "HELLO". I now wish to store these individual letters in a string on their own. Right now i have this code:

First I create a single string:

String readString;


Then I read my BTLEserial which is where I get the value that is being sent to the arduino and i store it in my string:

char c = BTLEserial.read();
readString += c;


readString now has the value "HELLO". Now i want to split it and what I have tried is to do it like this:

String stringOne = readString.substring (0,1); //H
String stringTwo = readString.substring (1,2); //E
String stringThree = readString.substring (2,3); //L
String stringFour = readString.substring (3,4); //L
String stringFive = readString.substring (4,5); //O


But with this i do not get the correct values in each string.

Appreciate every help I can get! :)
An array is 0 indexed, which means that number 5 is out of index. "Hello" should be index valued 0-4 and not 0-5. 

Here is a better code to try out: 

void setup() {
    Serial.begin(9600);
}

void loop() {

String recivedMessage = "";

// Read
while (Serial.available())
{
    recivedMessage += Serial.read();
}

// Print debug
Serial.print("recivedMessage: ");
Serial.println(recivedMessage);


//// Uncomment the row under if you are not sure that the splitting is working
// recivedMessage = "Hello";

// Split
char first  = recivedMessage.substring(0, 1)[0];    // H
char second = recivedMessage.substring(1, 2)[0];    // E
char third  = recivedMessage.substring(2, 3)[0];    // L
char forth  = recivedMessage.substring(3, 4)[0];    // L
char fifth  = recivedMessage.substring(4)[0];       // 0

// Print debug
Serial.print("Cut message: ");
Serial.println(first);
Serial.println(second);
Serial.println(third);
Serial.println(forth);
Serial.println(fifth);


}