button - Arduino - Action is being performed three times (DIY Game) -

i creating arduino project plays rock paper scissors you, have part of code reading value of button , whenever click 1 button, outputs 3 times (view code , images of serial monitor understand mean, can't explain it)

here code:

// constants won't change. they're used here  // set pin numbers: const int buttonpin1 = a0;     // number of pushbutton pin const int buttonpin2 = a1; const int buttonpin3 = a2; const int ledpin =  12;      // number of led pin  // variables change: int buttonstate1 = 0;         // variable reading pushbutton status int buttonstate2 = 0;  int buttonstate3 = 0;   char * choices[3] = {"rock", "paper", "scissors"}; char * finalresult[3] = {"you lost", "you won!", "it's tie"};  byte human = 0, computer = 0, fr = 0;  char result[25];  void setup() {   // initialize led pin output:   pinmode(ledpin, output);         // initialize pushbutton pin input:   pinmode(buttonpin1, input);   pinmode(buttonpin2, input);   pinmode(buttonpin3, input);   digitalwrite(ledpin,low);   serial.begin(9600);   unsigned long r;   randomseed(r); }  void loop(){   int choice = random(1,4);   int pick;   // read state of pushbutton value:     // check if pushbutton pressed.   // if is, buttonstate high:   serial.println("entering reading loop...");   while(true)   {     buttonstate1 = digitalread(buttonpin1);     buttonstate2 = digitalread(buttonpin2);     buttonstate3 = digitalread(buttonpin3);     if (buttonstate1 == high && buttonstate2 == low && buttonstate3 == low) {            // turn led on:           throw('1');      } else if (buttonstate1 == low && buttonstate2 == high && buttonstate3 == low) {            // turn led on:           pick = 2; //paper       throw('2');      }else if (buttonstate1 == low && buttonstate2 == low && buttonstate3 == high) {            // turn led on:           pick = 3; //scissor       throw('3');      }    } }  void throw(char h) {   bool thrown = false;   h -= '0'; //convert ascii decimal   h -= 1; // instead of  1,2,3, h 0,1,2    byte c = random(0, 3);    sprintf(result, "the computer chose: %s, chose: %s", choices[c], choices[h]);   serial.println(result);    if ( c == h)     serial.println(f("its tie"));   else   {     switch (c)     {       case 0:         switch (h)         {           case 1:             serial.println(f("paper wraps rock, win!"));             human++;             break;            case 2:             serial.println(f("rock crushes scissors, lose!"));             computer++;             break;         }         break;        case 1:         switch (h)         {           case 0:             serial.println(f("paper wraps rock, lose!"));             computer++;             break;            case 2:             serial.println(f("scissors cuts paper, win!"));             human++;             break;         }         break;        case 2:         switch (h)         {           case 0:             serial.println(f("rock crushes scissors, win!"));             human++;             break;            case 1:             serial.println(f("scissors cuts paper, lose!"));             computer++;             break;         }         break;     }   } } 

this im getting on serial monitor when click 1 button(the rock button)

http://gyazo.com/ceb5c8329993339368cf5d52181ed4d7

as can see, chooses right option button calls throw function 3 times.

i beginner(the throw function implemented source http://playground.arduino.cc/main/rockpaperscissors) please bare me if missed crucial information.

from arduino docs recommend using debounce strategy handling inputs.

without debouncing, pressing button once can appear code multiple presses.

http://www.arduino.cc/en/tutorial/debounce

here example illustrating debounce technique:

http://danthompsonsblog.blogspot.com/2011/12/arduino-push-button-onoff-example.html