Masqqq:
I'm sorry but I just began programming in Arduino so I don't really know how to do any of that.
No problem, you have to start somewhere. Do some research on arrays, they are very useful.
To get you started upload this program to your Arduino. Note that it is intended to illustrate many of the things that I suggested you do. It does NOT do what you described but might help you understand arrays
char password[] = {"ABCD"}; //an array of 4 chars (0 to 3)
byte index = 0; //index to the current chracter
void setup()
{
Serial.begin(115200);
}
void loop()
{
Serial.print("index : ");
Serial.print(index); //current value of index
Serial.print( " the letter at that position : ");
Serial.println(password[index]); //print the current letter
delay(1000); //wait a bit to slow things down in this demo
index++; //increment the index
if (index == 4) //if we have gone past the last letter
{
Serial.println("All done\n\n"); //print a message
delay(2000); //wait a while in this demo
index = 0; //put the index back to the start
return; //start the loop() function again
}
}