4 digit Button Press Counter

I am trying to make a button press counter. I currently am using an arduino as I have lots of them lying around and I cant afford any thing else. I have a four digit 7 segment display rigged up to an arduino uno. I need as I get easily get mad at work and I want to discretely find out how many times people make me mad throughout the day. At the moment it just reads the serial port/ RXTX lines but I need it to count button presses. Can someone help me out?

My code is:

[code]

int aPin = 2;  //                    

int bPin = 3;  //       

int cPin = 4;  //       

int dPin = 5;  //   

int ePin = 6;  //       

int fPin = 7;  //        

int gPin = 8;  //        

int GND1 = 9;  //      

int GND2 = 10; //  

int GND3 = 11; //    

int GND4 = 12; //      

int num;      

int dig1 = 0;

int dig2 = 0;

int dig3 = 0;

int dig4 = 0;

int DTime = 4;

void setup()

{

  pinMode(aPin, OUTPUT);

  pinMode(bPin, OUTPUT);

  pinMode(cPin, OUTPUT);

  pinMode(dPin, OUTPUT);

  pinMode(ePin, OUTPUT);

  pinMode(fPin, OUTPUT);

  pinMode(gPin, OUTPUT);

  pinMode(GND1, OUTPUT);

  pinMode(GND2, OUTPUT);

  pinMode(GND3, OUTPUT);

  pinMode(GND4, OUTPUT);

  Serial.begin(9600);

}

void loop()

{

  digitalWrite( GND1, HIGH);

  digitalWrite( GND2, HIGH);

  digitalWrite( GND3, HIGH);

  digitalWrite( GND4, HIGH);

if (Serial.available() > 0)

{

  num = Serial.parseInt();

  Serial.println(num);

  dig1 = num / 1000;

  num = num - (dig1 * 1000);

  dig2 = num / 100;

  num = num - (dig2 * 100);

  dig3 = num / 10;

  dig4 = num - (dig3 *10);

}

  digitalWrite( GND4, LOW);    //digit 4

  pickNumber(dig4);

  delay(DTime);

  digitalWrite( GND4, HIGH);

  digitalWrite( GND3, LOW);    //digit 3

  pickNumber(dig3);

  delay(DTime);

  digitalWrite( GND3, HIGH);

  digitalWrite( GND2, LOW);   //digit 2

  pickNumber(dig2);

  delay(DTime);

  digitalWrite( GND2, HIGH);

  digitalWrite( GND1, LOW);   //digit 1

  pickNumber(dig1);

  delay(DTime);

  digitalWrite( GND1, HIGH);

}

void pickNumber(int x){

   switch(x){

     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;

     default: zero(); break;

   }

}

void clearLEDs()

{ 

  digitalWrite(  2, LOW); // A

  digitalWrite(  3, LOW); // B

  digitalWrite(  4, LOW); // C

  digitalWrite(  5, LOW); // D

  digitalWrite(  6, LOW); // E

  digitalWrite(  7, LOW); // F

  digitalWrite(  8, LOW); // G

}

void one()

{

  digitalWrite( aPin, LOW);

  digitalWrite( bPin, HIGH);

  digitalWrite( cPin, HIGH);

  digitalWrite( dPin, LOW);

  digitalWrite( ePin, LOW);

  digitalWrite( fPin, LOW);

  digitalWrite( gPin, LOW);

}

void two()

{

  digitalWrite( aPin, HIGH);

  digitalWrite( bPin, HIGH);

  digitalWrite( cPin, LOW);

  digitalWrite( dPin, HIGH);

  digitalWrite( ePin, HIGH);

  digitalWrite( fPin, LOW);

  digitalWrite( gPin, HIGH);

}

void three()

{

  digitalWrite( aPin, HIGH);

  digitalWrite( bPin, HIGH);

  digitalWrite( cPin, HIGH);

  digitalWrite( dPin, HIGH);

  digitalWrite( ePin, LOW);

  digitalWrite( fPin, LOW);

  digitalWrite( gPin, HIGH);

}

void four()

{

  digitalWrite( aPin, LOW);

  digitalWrite( bPin, HIGH);

  digitalWrite( cPin, HIGH);

  digitalWrite( dPin, LOW);

  digitalWrite( ePin, LOW);

  digitalWrite( fPin, HIGH);

  digitalWrite( gPin, HIGH);

}

void five()

{

  digitalWrite( aPin, HIGH);

  digitalWrite( bPin, LOW);

  digitalWrite( cPin, HIGH);

  digitalWrite( dPin, HIGH);

  digitalWrite( ePin, LOW);

  digitalWrite( fPin, HIGH);

  digitalWrite( gPin, HIGH);

}

void six()

{

  digitalWrite( aPin, HIGH);

  digitalWrite( bPin, LOW);

  digitalWrite( cPin, HIGH);

  digitalWrite( dPin, HIGH);

  digitalWrite( ePin, HIGH);

  digitalWrite( fPin, HIGH);

  digitalWrite( gPin, HIGH);

}

void seven()

{

  digitalWrite( aPin, HIGH);

  digitalWrite( bPin, HIGH);

  digitalWrite( cPin, HIGH);

  digitalWrite( dPin, LOW);

  digitalWrite( ePin, LOW);

  digitalWrite( fPin, LOW);

  digitalWrite( gPin, LOW);

}

void eight()

{

  digitalWrite( aPin, HIGH);

  digitalWrite( bPin, HIGH);

  digitalWrite( cPin, HIGH);

  digitalWrite( dPin, HIGH);

  digitalWrite( ePin, HIGH);

  digitalWrite( fPin, HIGH);

  digitalWrite( gPin, HIGH);

}

void nine()

{

  digitalWrite( aPin, HIGH);

  digitalWrite( bPin, HIGH);

  digitalWrite( cPin, HIGH);

  digitalWrite( dPin, HIGH);

  digitalWrite( ePin, LOW);

  digitalWrite( fPin, HIGH);

  digitalWrite( gPin, HIGH);

}

void zero()

{

  digitalWrite( aPin, HIGH);

  digitalWrite( bPin, HIGH);

  digitalWrite( cPin, HIGH);

  digitalWrite( dPin, HIGH);

  digitalWrite( ePin, HIGH);

  digitalWrite( fPin, HIGH);

  digitalWrite( gPin, LOW);

}

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