int buton;
const byte a = 8, b = 5, c = 4, d = 3, e = 2, f = 1, g = 0;
int sayac = 0;

void setup() {
for (byte i = 0; i <= 6; i++) {
 pinMode(i, OUTPUT); // 0 - 6 pinleri çıkış yap.
}
}
void loop() {
buton=digitalRead(7);
if(buton==1)
{
  sayac==sayac+1;
  delay(300);
}
yazdir(sayac);
}

void yazdir (byte rakam){
  switch(rakam)
{

 case 0 :
 digitalWrite(a, HIGH);
 digitalWrite(b, HIGH);
 digitalWrite(c, HIGH);
 digitalWrite(d, HIGH);
 digitalWrite(e, HIGH);
 digitalWrite(f, HIGH);
 digitalWrite(g, LOW);
 break;
 case 1:
 digitalWrite(a, LOW);
 digitalWrite(b, HIGH);
 digitalWrite(c, HIGH);
 digitalWrite(d, LOW);
 digitalWrite(e, LOW);
 digitalWrite(f, LOW);
 digitalWrite(g, LOW);
 break;
 case 2:
 digitalWrite(a, HIGH);
 digitalWrite(b, HIGH);
 digitalWrite(c, LOW);
 digitalWrite(d, HIGH);
 digitalWrite(e, HIGH);
 digitalWrite(f, LOW);
 digitalWrite(g, HIGH);
 break;
 case 3:
 digitalWrite(a, HIGH);
 digitalWrite(b, HIGH);
 digitalWrite(c, HIGH);
 digitalWrite(d, HIGH);
 digitalWrite(e, LOW);
 digitalWrite(f, LOW);
 digitalWrite(g, HIGH);
 break;
 case 4:
 digitalWrite(a, LOW);
 digitalWrite(b, HIGH);
 digitalWrite(c, HIGH);
 digitalWrite(d, LOW);
 digitalWrite(e, LOW);
 digitalWrite(f, HIGH);
 digitalWrite(g, HIGH);
 break;
 case 5:
 digitalWrite(a, HIGH);
 digitalWrite(b, LOW);
 digitalWrite(c, HIGH);
 digitalWrite(d, HIGH);
 digitalWrite(e, LOW);
 digitalWrite(f, HIGH);
 digitalWrite(g, HIGH);
 break;
 case 6:
 digitalWrite(a, HIGH);
 digitalWrite(b, LOW);
 digitalWrite(c, HIGH);
 digitalWrite(d, HIGH);
 digitalWrite(e, HIGH);
 digitalWrite(f, HIGH);
 digitalWrite(g, HIGH);
 break;
 case 7:
 digitalWrite(a, HIGH);
 digitalWrite(b, HIGH);
 digitalWrite(d, HIGH);
 digitalWrite(e, LOW);
 digitalWrite(f, HIGH);
 digitalWrite(g, HIGH);
 break;
}
}