#define a 2
    #define b 3
    #define c 4
    #define d 5
    #define e 6
    #define f 7
    #define g 8

    #define inc 12
    #define dec 13

    int num=0,vIncPrev,vDecPrev;

    void setup() {
        pinMode(inc,INPUT);
        pinMode(dec,INPUT);

        pinMode(a, OUTPUT);
        pinMode(b, OUTPUT);
        pinMode(c, OUTPUT);
        pinMode(d, OUTPUT);
        pinMode(e, OUTPUT);
        pinMode(f, OUTPUT);
        pinMode(g, OUTPUT);
    }

    void zero(){
        digitalWrite(a, HIGH);
        digitalWrite(b, HIGH);
        digitalWrite(c, HIGH);
        digitalWrite(d, HIGH);
        digitalWrite(e, HIGH);
        digitalWrite(f, HIGH);
        digitalWrite(g, LOW);
    }

    void one(){
        digitalWrite(a, LOW);
        digitalWrite(b, HIGH);
        digitalWrite(c, HIGH);
        digitalWrite(d, LOW);
        digitalWrite(e, LOW);
        digitalWrite(f, LOW);
        digitalWrite(g, LOW);
    }

    void two(){
        digitalWrite(a, HIGH);
        digitalWrite(b, HIGH);
        digitalWrite(c, LOW);
        digitalWrite(d, HIGH);
        digitalWrite(e, HIGH);
        digitalWrite(f, LOW);
        digitalWrite(g, HIGH);
    }

    void three(){
        digitalWrite(a, HIGH);
        digitalWrite(b, HIGH);
        digitalWrite(c, HIGH);
        digitalWrite(d, HIGH);
        digitalWrite(e, LOW);
        digitalWrite(f, LOW);
        digitalWrite(g, HIGH);
    }

    void four(){
        digitalWrite(a, LOW);
        digitalWrite(b, HIGH);
        digitalWrite(c, HIGH);
        digitalWrite(d, LOW);
        digitalWrite(e, LOW);
        digitalWrite(f, HIGH);
        digitalWrite(g, HIGH);
    }

    void five(){
        digitalWrite(a, HIGH);
        digitalWrite(b, LOW);
        digitalWrite(c, HIGH);
        digitalWrite(d, HIGH);
        digitalWrite(e, LOW);
        digitalWrite(f, HIGH);
        digitalWrite(g, HIGH);
    }

    void six(){
        digitalWrite(a, HIGH);
        digitalWrite(b, LOW);
        digitalWrite(c, HIGH);
        digitalWrite(d, HIGH);
        digitalWrite(e, HIGH);
        digitalWrite(f, HIGH);
        digitalWrite(g, HIGH);
    }

    void seven(){
        digitalWrite(a, HIGH);
        digitalWrite(b, HIGH);
        digitalWrite(c, HIGH);
        digitalWrite(d, LOW);
        digitalWrite(e, LOW);
        digitalWrite(f, LOW);
        digitalWrite(g, LOW);
    }

    void eight(){
        digitalWrite(a, HIGH);
        digitalWrite(b, HIGH);
        digitalWrite(c, HIGH);
        digitalWrite(d, HIGH);
        digitalWrite(e, HIGH);
        digitalWrite(f, HIGH);
        digitalWrite(g, HIGH);
    }

    void nine(){
        digitalWrite(a, HIGH);
        digitalWrite(b, HIGH);
        digitalWrite(c, HIGH);
        digitalWrite(d, HIGH);
        digitalWrite(e, LOW);
        digitalWrite(f, HIGH);
        digitalWrite(g, HIGH);
    }

    void displayNum(int num){
    switch(num){
        case 0:
        zero();
        break;

        case 1:
        one();
        break;
        
        case 2:
        two();
        break;

        case 3:
        three();
        break;

        case 4:
        four();
        break;

        case 5:
        five();
        break;

        case 6:
        six();
        break;

        case 7:
        seven();
        break;

        case 8:
        eight();
        break;

        case 9:
        nine();
        break;
    }
    }

    void loop() {
        int vInc=digitalRead(inc);
        int vDec=digitalRead(dec);
        displayNum(num); 

        if ((vInc == HIGH) && num<=9) {
            delay(100);
            while (digitalRead(inc) == HIGH);
            num++;  
            displayNum(num); 
        }

        if ((vDec == HIGH) && num>=0) {
            delay(100);
            while (digitalRead(dec) == HIGH);
            num--; 
            displayNum(num); 
        }
    }