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This example is for Wiring version 1.0 build 0100+. If you have a previous version, use the examples included with your software. If you see any errors or have comments, please let us know.

Iteration over digital inputs.
Iteration with a "for" structure over input pins. button switches are wired from pins 8 to 11 depending the number of pressed buttons a variable named "force" will hold different values from 0 to 4

    int force;

    void setup()
    {
      Serial.begin(9600);
      for (int i = 8; i < 12; i++)   // sets pins 0-3 as inputs
      {
        pinMode(i, INPUT);
      }
    }

    void loop()
    {
      force = 0;
      for (int i = 8; i < 12; i++)   // calculates how many buttons are pressed
      {
        if (digitalRead(i) == HIGH)
        {
          force = force + 1;  // add 1 to force if the button is pressed
        }
      }
      Serial.print("force is: ");  // print the force value
      Serial.println(force, DEC);
      delay(200);  // wait 200ms for next reading
    }