Hi
when i wanna verify this program,this message('serial' was not declared in this scope) appears on screen and i can't understand what the matter is!!
please help me solve this problem. 
my project is:
void setup() {
// put your setup code here, to run once:
serial.begin(9600);
}
void loop() {
// put your main code here, to run repeatedly:
if(serial.available()>0){
char data=serial.read();
serial.println(data);
}
}
