String number; // reads the number from the serial monitor
// declared the output oin of 7 segment with arduino
const int a=2; 
const int b=3;
const int c=4;
const int d=5;
const int e=6;
const int f=7;
const int g=8;
const int com=9;  
int valid=1; // variable to check its valid umber given by the users or not

void setup() {
  // put your setup code here, to run once:
// set the pins as OUTPUT
pinMode(a,OUTPUT);  
pinMode(b,OUTPUT);
pinMode(c,OUTPUT);
pinMode(d,OUTPUT);
pinMode(e,OUTPUT);
pinMode(f,OUTPUT);
pinMode(g,OUTPUT);
pinMode(com,OUTPUT);
Serial.begin(9600); // begin the serial monitor
 
}

void loop() {
while (Serial.available()==0){} // checking is there any input is available
number=Serial.readString();     // read the number from the serial monitor


// if the number input is valid then this loop will work and display it
if (valid==1){
char val=number.charAt(0);// store the number into the char variable 'val'
// check wether input number is valid hexadecimal number(0-F)
if ((val>47 && val<58)||(val>64 & val<71)){//comapre by ASCII values od 0-9 & A-F
  
  Serial.print(val);
  Serial.println("");
}


//0
if (val==48)
{

digitalWrite(a,LOW);
digitalWrite(b,LOW);
digitalWrite(c,LOW);
digitalWrite(d,LOW);
digitalWrite(e,LOW);
digitalWrite(f,LOW);
digitalWrite(g,HIGH);
digitalWrite(com,HIGH);
}

//1
 if (val==49)
{
digitalWrite(a,1);
digitalWrite(b,0);
digitalWrite(c,0);
digitalWrite(d,1);
digitalWrite(e,1);
digitalWrite(f,1);
digitalWrite(g,1);
digitalWrite(com,HIGH);

}

//2
if (val==50)
{
digitalWrite(a,HIGH);
digitalWrite(b,HIGH);
digitalWrite(c,LOW);
digitalWrite(d,HIGH);
digitalWrite(e,HIGH);
digitalWrite(f,LOW);
digitalWrite(g,HIGH);
}

//3
if (val==51)
{digitalWrite(a,HIGH);
digitalWrite(b,HIGH);
digitalWrite(c,HIGH);
digitalWrite(d,HIGH);
digitalWrite(e,LOW);
digitalWrite(f,LOW);
digitalWrite(g,HIGH);
}

//4
if (val==52)
{
digitalWrite(a,LOW);
digitalWrite(b,HIGH);
digitalWrite(c,HIGH);
digitalWrite(d,LOW);
digitalWrite(e,LOW);
digitalWrite(f,HIGH);
digitalWrite(g,HIGH);
}

//5
if (val==53)
{
digitalWrite(a,HIGH);
digitalWrite(b,LOW);
digitalWrite(c,HIGH);
digitalWrite(d,HIGH);
digitalWrite(e,LOW);
digitalWrite(f,HIGH);
digitalWrite(g,HIGH);
}

//6
if (val==54)
{
digitalWrite(a,HIGH);
digitalWrite(b,LOW);
digitalWrite(c,HIGH);
digitalWrite(d,HIGH);
digitalWrite(e,HIGH);
digitalWrite(f,HIGH);
digitalWrite(g,HIGH);
}

//7
if (val==55)
{
digitalWrite(a,HIGH);
digitalWrite(b,HIGH);
digitalWrite(c,HIGH);
digitalWrite(d,LOW);
digitalWrite(e,LOW);
digitalWrite(f,LOW);
digitalWrite(g,LOW);
}

//8
if (val==56)
{
digitalWrite(a,HIGH);
digitalWrite(b,HIGH);
digitalWrite(c,HIGH);
digitalWrite(d,HIGH);
digitalWrite(e,HIGH);
digitalWrite(f,HIGH);
digitalWrite(g,HIGH);

}

//9
if (val==57)
{
digitalWrite(a,HIGH);
digitalWrite(b,HIGH);
digitalWrite(c,HIGH);
digitalWrite(d,HIGH);
digitalWrite(e,LOW);
digitalWrite(f,HIGH);
digitalWrite(g,HIGH);
}

//A
if (val==65)
{
digitalWrite(a,HIGH);
digitalWrite(b,HIGH);
digitalWrite(c,HIGH);
digitalWrite(d,LOW);
digitalWrite(e,HIGH);
digitalWrite(f,HIGH);
digitalWrite(g,HIGH);
}

//B
if (val==66)
{
digitalWrite(a,LOW);
digitalWrite(b,LOW);
digitalWrite(c,HIGH);
digitalWrite(d,HIGH);
digitalWrite(e,HIGH);
digitalWrite(f,HIGH);
digitalWrite(g,HIGH);
}

//C
if (val==67)
{
digitalWrite(a,HIGH);
digitalWrite(b,LOW);
digitalWrite(c,LOW);
digitalWrite(d,HIGH);
digitalWrite(e,HIGH);
digitalWrite(f,HIGH);
digitalWrite(g,HIGH);
}

//D
if (val==68)
{
digitalWrite(a,LOW);
digitalWrite(b,HIGH);
digitalWrite(c,HIGH);
digitalWrite(d,HIGH);
digitalWrite(e,HIGH);
digitalWrite(f,LOW);
digitalWrite(g,HIGH);
}

//E
 if (val==69)
{
digitalWrite(a,HIGH);
digitalWrite(b,LOW);
digitalWrite(c,LOW);
digitalWrite(d,HIGH);
digitalWrite(e,HIGH);
digitalWrite(f,HIGH);
digitalWrite(g,HIGH);
}

//F
if (val==70)
{
digitalWrite(a,HIGH);
digitalWrite(b,LOW);
digitalWrite(c,LOW);
digitalWrite(d,LOW);
digitalWrite(e,HIGH);
digitalWrite(f,HIGH);
digitalWrite(g,HIGH);
}
delay(3000);
}
}