Making lettercheck not case sensitive - c++

Question

So I need to make this code be able to count the a specified letter (In this case the letter E). I've made it to the point where it counts how many times in the sentence the letter has been typed, however it is case sensitive. Right now it only counts upper-case E, which can be changed but I can't figure out how it'll read both upper and lower-case.
I've found the equalsIgnoreCase() code, however I'm not familiar with it so I don't know where to put it, how it works or if it even will work. In my case, I tried myString.equalsIgnoreCase(MyString2), in my case CharCount and CharCountLow I believe.
This is my code:
//Written sentence gets read by arduino when enter is pressed and printed into the serial monitor
//Arduino counts how many characters are in the sentence and prints out that number in serial monitor
//Arduino then counts how many times any chosen letter in the sentence is written, for example E, and then prints out that number on the monitor.
//Arduino then reads the sentence you've written and prints it backwards in serial monitor
char Message[128] = "";
char MessageInversed[128] = "";
static int CharCount;
char NextChar;
char CountChar = 'E';
char CountCharLow = 'e'; // this is what I've tried
int Counter;
boolean Done;
void setup()
{
// put your setup code here, to run once:
Serial.begin(9600);
Serial.println("<Enter your text>");
}
void loop()
{
Readmessage();
Showmessage();
}
void Readmessage()
{
static int CharCount = 0;
char EnterCheck = '\n';
while (Serial.available() > 0 && Done == false)
{
NextChar = Serial.read();
if (NextChar == CountChar || CountCharLow) // this is what I've tried
{
Counter++;
}
if (NextChar != EnterCheck)
{
Message[CharCount] = NextChar;
CharCount++;
}
else
{
InverseMessage(CharCount);
Message[CharCount-1] = '\0';
CharCount=0;
Done = true;
}
}
}
void InverseMessage(int Characters)
{
for (int InversedCharCount = 0; InversedCharCount < Characters-1; InversedCharCount++)
{
MessageInversed[Characters-2-InversedCharCount] = Message[InversedCharCount];
}
MessageInversed[Characters] = '\0';
}
void Showmessage()
{
if (Done == true)
{
Serial.print("Your message length is: ");
Serial.println(strlen(Message));
Serial.print("This is your message: ");
Serial.println(Message);
Serial.print("Your inversed message length is: ");
Serial.println(strlen(MessageInversed));
Serial.print("Your reversed message is: ");
Serial.println(MessageInversed);
if (Counter == 1)
{
Serial.print("The letter E has been typed ");
Serial.print(Counter);
Serial.println(" time");
}
else
{
Serial.print("The letter E has been typed a total of ");
Serial.print(Counter);
Serial.println(" times");
}
Serial.print("<Please enter next text>");
Done = false;
Counter = 0;
}
}

Answer 1

You need to check if the NextChar is the lower case letter, so it should work by typing:
if(NextChar == CountChar || NextChar == CountCharLow) {...}