int a = 1;
int b = 2;
int c = 3;
int d = 4;
int e = 5;
int f = 6;
int g = 7;
int dp = 8;
// select pin for anode
int d4 = 9;
int d3 = 10;
int d2 = 11;
int d1 = 12;
// set variable
long n = 1230;
int x = 100;
int del = 55; // fine adjustment for clock
void setup()
{
pinMode(d1, OUTPUT);
pinMode(d2, OUTPUT);
pinMode(d3, OUTPUT);
pinMode(d4, OUTPUT);
pinMode(a, OUTPUT);
pinMode(b, OUTPUT);
pinMode(c, OUTPUT);
pinMode(d, OUTPUT);
pinMode(e, OUTPUT);
pinMode(f, OUTPUT);
pinMode(g, OUTPUT);
pinMode(dp, OUTPUT);
}
/////////////////////////////////////////////////////////////
void loop()
{
Display(1, 1);
Display(2, 2);
Display(3, 3);
Display(4, 4);
}
///////////////////////////////////////////////////////////////
void WeiXuan(unsigned char n)//
{
switch(n)
{
case 1:
digitalWrite(d1,LOW);
digitalWrite(d2, HIGH);
digitalWrite(d3, HIGH);
digitalWrite(d4, HIGH);
break;
case 2:
digitalWrite(d1, HIGH);
digitalWrite(d2, LOW);
digitalWrite(d3, HIGH);
digitalWrite(d4, HIGH);
break;
case 3:
digitalWrite(d1,HIGH);
digitalWrite(d2, HIGH);
digitalWrite(d3, LOW);
digitalWrite(d4, HIGH);
break;
case 4:
digitalWrite(d1, HIGH);
digitalWrite(d2, HIGH);
digitalWrite(d3, HIGH);
digitalWrite(d4, LOW);
break;
default :
digitalWrite(d1, HIGH);
digitalWrite(d2, HIGH);
digitalWrite(d3, HIGH);
digitalWrite(d4, HIGH);
break;
}
}
void Num_0()
{
digitalWrite(a, HIGH);
digitalWrite(b, HIGH);
digitalWrite(c, HIGH);
digitalWrite(d, HIGH);
digitalWrite(e, HIGH);
digitalWrite(f, HIGH);
digitalWrite(g, LOW);
digitalWrite(dp,LOW);
}
void Num_1()
{
digitalWrite(a, LOW);
digitalWrite(b, HIGH);
digitalWrite(c, HIGH);
digitalWrite(d, LOW);
digitalWrite(e, LOW);
digitalWrite(f, LOW);
digitalWrite(g, LOW);
digitalWrite(dp,LOW);
}
void Num_2()
{
digitalWrite(a, HIGH);
digitalWrite(b, HIGH);
digitalWrite(c, LOW);
digitalWrite(d, HIGH);
digitalWrite(e, HIGH);
digitalWrite(f, LOW);
digitalWrite(g, HIGH);
digitalWrite(dp,LOW);
}
void Num_3()
{
digitalWrite(a, HIGH);
digitalWrite(b, HIGH);
digitalWrite(c, HIGH);
digitalWrite(d, HIGH);
digitalWrite(e, LOW);
digitalWrite(f, LOW);
digitalWrite(g, HIGH);
digitalWrite(dp,LOW);
}
void Num_4()
{
digitalWrite(a, LOW);
digitalWrite(b, HIGH);
digitalWrite(c, HIGH);
digitalWrite(d, LOW);
digitalWrite(e, LOW);
digitalWrite(f, HIGH);
digitalWrite(g, HIGH);
digitalWrite(dp,LOW);
}

void Clear() // clear the screen
{
digitalWrite(a, LOW);
digitalWrite(b, LOW);
digitalWrite(c, LOW);
digitalWrite(d, LOW);
digitalWrite(e, LOW);
digitalWrite(f, LOW);
digitalWrite(g, LOW);
digitalWrite(dp,LOW);
}
void pickNumber(unsigned char n)// select number
{
switch(n)
{
case 0:Num_0();
break;
case 1:Num_1();
break;
case 2:Num_2();
break;
case 3:Num_3();
break;
case 4:Num_4();
break;
default:Clear();
break;
}
}
void Display(unsigned char x, unsigned char Number)// take x as coordinate and display number
{
  WeiXuan(x);
  pickNumber(Number);
  //delay(1);
  Clear() ; // clear the screen
}