user4137: I'm working on modifying this example from the Arduino website to read the state of 3 toggle (SPDT) switches. If I have one toggle switch hooked up, my sketch works as expected...the sketch will log the state of the switch in the serial debugger every-time the state changes, and only when the state changes. 
However, if I add in two more switches, the serial debugger will continuously output my log messages, without detecting if the state has changed. 
Here's the code from my sketch: 
const int  switchOnePin = 2;    // digital in 2 (pin the switch one is attached to)
const int  switchTwoPin = 3;    // digital in 3 (pin the switch two is attached to)
const int  switchThreePin = 4;  // digital in 4 (pin the switch three is attached to)

int switchOneState = 0;         // current state of the switch
int lastSwitchOneState = 0;     // previous state of the switch

int switchTwoState = 0;         
int lastSwitchTwoState = 0;     

int switchThreeState = 0;         
int lastSwitchThreeState = 0;     


void setup() {
  // initialize serial communication at 9600 bits per second:
  Serial.begin(9600);

  int switchOneState = 0;         // current state of the switch
  int lastSwitchOneState = 0;     // previous state of the switch switch pins as an input
  pinMode(switchOnePin, INPUT);
  pinMode(switchTwoPin, INPUT);
  pinMode(switchThreePin, INPUT);
}


void loop() {

  // read the switch input pins:
  switchOneState   = digitalRead(switchOnePin);
  delay(50);
  switchTwoState   = digitalRead(switchTwoPin);
  delay(50);
  switchThreeState = digitalRead(switchThreePin);

  // compare the switchState to its previous state
  if (switchOneState != lastSwitchOneState) {
  // if the state has changed, increment the counter
    if (switchOneState == HIGH) {
    // if the current state is HIGH then the button
    // went from off to on:
    Serial.println("Switch one is on");
  }
  else {
    // if the current state is LOW then the button
    // went from on to off:
    Serial.println("Switch one is off");
  }




  if (switchTwoState != lastSwitchTwoState) {
    if (switchTwoState == HIGH) {
    Serial.println("Switch two is on");
  }
  else {
    Serial.println("Switch two is off");
  }

  if (switchThreeState != lastSwitchThreeState) {
    if (switchThreeState == HIGH) {
    Serial.println("Switch three is on");
  }
  else {
    Serial.println("Switch thre is off");
  }
 }
}
  // Delay a little bit to avoid bouncing
  delay(50);  
}
// save the current state as the last state,
//for next time through the loop
lastSwitchOneState   = switchOnePin;
lastSwitchTwoState   = switchTwoPin;
lastSwitchThreeState = switchThreePin;
}

And here's what my circuit looks like: 

Does anyone have any insight into what I may be doing wrong? I'm not quite sure if it's a circuit or a sketch issue (or both). 
EDIT I tried adding a delay of 50ms between each digital input read, but that still did not seem to help the problem. 

user2881: lastSwitchOneState   = switchOnePin;
lastSwitchTwoState   = switchTwoPin;
lastSwitchThreeState = switchThreePin;

should be  
lastSwitchOneState   = switchOneState;
lastSwitchTwoState   = switchTwoState;
lastSwitchThreeState = switchThreeState;


user4137: The problem was two pronged---both the copy/paste error that @Gerben pointed out, as well as the incorrect if-else statements that @BrettAM pointed out. Below is the working code: 
const int  switchOnePin = 2;    // digital in 2 (pin the switch one is attached to)
const int  switchTwoPin = 3;    // digital in 3 (pin the switch two is attached to)
const int  switchThreePin = 4;  // digital in 4 (pin the switch three is attached to)

int switchOneState = 0;         // current state of the switch
int lastSwitchOneState = 0;     // previous state of the switch

int switchTwoState = 0;
int lastSwitchTwoState = 0;

int switchThreeState = 0;
int lastSwitchThreeState = 0;


void setup() {
    //initialize serial communication at 9600 bits per second:
    Serial.begin(9600);

    int switchOneState = 0;         // current state of the switch
    int lastSwitchOneState = 0;     // previous state of the switch switch pins as an input
    pinMode(switchOnePin, INPUT);
    pinMode(switchTwoPin, INPUT);
    pinMode(switchThreePin, INPUT);
}

void loop() {
    // read the switch input pins:
    switchOneState   = digitalRead(switchOnePin);
    switchTwoState   = digitalRead(switchTwoPin);
    switchThreeState = digitalRead(switchThreePin);

    // compare the switchState to its previous state
    if (switchOneState != lastSwitchOneState) {
        // if the state has changed, increment the counter
        if (switchOneState == HIGH) {
        // if the current state is HIGH then the button
        // went from off to on:
            Serial.println("Switch one is on");
        } else {
            // if the current state is LOW then the button
            // went from on to off:
            Serial.println("Switch one is off");
        }
    }

    if (switchTwoState != lastSwitchTwoState) {
        if (switchTwoState == HIGH) {
            Serial.println("Switch two is on");
        } else {
            Serial.println("Switch two is off");
        }
    }

    if (switchThreeState != lastSwitchThreeState) {
        if (switchThreeState == HIGH) {
            Serial.println("Switch three is on");
        } else {
            Serial.println("Switch thre is off");
        }
    }

    // Delay a little bit to avoid bouncing
    delay(50);

    // save the current state as the last state,
    //for next time through the loop
    lastSwitchOneState   = switchOneState;
    lastSwitchTwoState   = switchTwoState;
    lastSwitchThreeState = switchThreeState;
}


4137: <p>I'm working on modifying this <a href="https://www.arduino.cc/en/Tutorial/Switch" rel="nofollow noreferrer">example</a> from the Arduino website to read the state of 3 toggle (SPDT) switches. If I have one toggle switch hooked up, my sketch works as expected...the sketch will log the state of the switch in the serial debugger every-time the state changes, and only when the state changes. </p>

<p>However, if I add in two more switches, the serial debugger will continuously output my log messages, without detecting if the state has changed. </p>

<p>Here's the code from my sketch: </p>

<pre><code>const int  switchOnePin = 2;    // digital in 2 (pin the switch one is attached to)
const int  switchTwoPin = 3;    // digital in 3 (pin the switch two is attached to)
const int  switchThreePin = 4;  // digital in 4 (pin the switch three is attached to)

int switchOneState = 0;         // current state of the switch
int lastSwitchOneState = 0;     // previous state of the switch

int switchTwoState = 0;         
int lastSwitchTwoState = 0;     

int switchThreeState = 0;         
int lastSwitchThreeState = 0;     


void setup() {
  // initialize serial communication at 9600 bits per second:
  Serial.begin(9600);

  int switchOneState = 0;         // current state of the switch
  int lastSwitchOneState = 0;     // previous state of the switch switch pins as an input
  pinMode(switchOnePin, INPUT);
  pinMode(switchTwoPin, INPUT);
  pinMode(switchThreePin, INPUT);
}


void loop() {

  // read the switch input pins:
  switchOneState   = digitalRead(switchOnePin);
  delay(50);
  switchTwoState   = digitalRead(switchTwoPin);
  delay(50);
  switchThreeState = digitalRead(switchThreePin);

  // compare the switchState to its previous state
  if (switchOneState != lastSwitchOneState) {
  // if the state has changed, increment the counter
    if (switchOneState == HIGH) {
    // if the current state is HIGH then the button
    // went from off to on:
    Serial.println("Switch one is on");
  }
  else {
    // if the current state is LOW then the button
    // went from on to off:
    Serial.println("Switch one is off");
  }




  if (switchTwoState != lastSwitchTwoState) {
    if (switchTwoState == HIGH) {
    Serial.println("Switch two is on");
  }
  else {
    Serial.println("Switch two is off");
  }

  if (switchThreeState != lastSwitchThreeState) {
    if (switchThreeState == HIGH) {
    Serial.println("Switch three is on");
  }
  else {
    Serial.println("Switch thre is off");
  }
 }
}
  // Delay a little bit to avoid bouncing
  delay(50);  
}
// save the current state as the last state,
//for next time through the loop
lastSwitchOneState   = switchOnePin;
lastSwitchTwoState   = switchTwoPin;
lastSwitchThreeState = switchThreePin;
}
</code></pre>

<p>And here's what my circuit looks like: </p>

<p><a href="https://i.stack.imgur.com/ZLAB6.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/ZLAB6.png" alt="enter image description here"></a>
Does anyone have any insight into what I may be doing wrong? I'm not quite sure if it's a circuit or a sketch issue (or both). </p>

<p><strong>EDIT</strong> I tried adding a delay of 50ms between each digital input read, but that still did not seem to help the problem. </p>
 2881: <pre><code>lastSwitchOneState   = switchOnePin;
lastSwitchTwoState   = switchTwoPin;
lastSwitchThreeState = switchThreePin;
</code></pre>

<p>should be  </p>

<pre><code>lastSwitchOneState   = switchOneState;
lastSwitchTwoState   = switchTwoState;
lastSwitchThreeState = switchThreeState;
</code></pre>
 4137: <p>The problem was two pronged---both the copy/paste error that @Gerben pointed out, as well as the incorrect if-else statements that @BrettAM pointed out. Below is the working code: </p>

<pre><code>const int  switchOnePin = 2;    // digital in 2 (pin the switch one is attached to)
const int  switchTwoPin = 3;    // digital in 3 (pin the switch two is attached to)
const int  switchThreePin = 4;  // digital in 4 (pin the switch three is attached to)

int switchOneState = 0;         // current state of the switch
int lastSwitchOneState = 0;     // previous state of the switch

int switchTwoState = 0;
int lastSwitchTwoState = 0;

int switchThreeState = 0;
int lastSwitchThreeState = 0;


void setup() {
    //initialize serial communication at 9600 bits per second:
    Serial.begin(9600);

    int switchOneState = 0;         // current state of the switch
    int lastSwitchOneState = 0;     // previous state of the switch switch pins as an input
    pinMode(switchOnePin, INPUT);
    pinMode(switchTwoPin, INPUT);
    pinMode(switchThreePin, INPUT);
}

void loop() {
    // read the switch input pins:
    switchOneState   = digitalRead(switchOnePin);
    switchTwoState   = digitalRead(switchTwoPin);
    switchThreeState = digitalRead(switchThreePin);

    // compare the switchState to its previous state
    if (switchOneState != lastSwitchOneState) {
        // if the state has changed, increment the counter
        if (switchOneState == HIGH) {
        // if the current state is HIGH then the button
        // went from off to on:
            Serial.println("Switch one is on");
        } else {
            // if the current state is LOW then the button
            // went from on to off:
            Serial.println("Switch one is off");
        }
    }

    if (switchTwoState != lastSwitchTwoState) {
        if (switchTwoState == HIGH) {
            Serial.println("Switch two is on");
        } else {
            Serial.println("Switch two is off");
        }
    }

    if (switchThreeState != lastSwitchThreeState) {
        if (switchThreeState == HIGH) {
            Serial.println("Switch three is on");
        } else {
            Serial.println("Switch thre is off");
        }
    }

    // Delay a little bit to avoid bouncing
    delay(50);

    // save the current state as the last state,
    //for next time through the loop
    lastSwitchOneState   = switchOneState;
    lastSwitchTwoState   = switchTwoState;
    lastSwitchThreeState = switchThreeState;
}
</code></pre>
