Button without ground and 5v

Other Hardware General Electronics
8

In a pinch you can wire the switch like in your diagram in the original post. Set one pin to output and write it LOW. Set the other to INPUT_PULLUP. When you read the input, the input will be HIGH for a switch that is not pressed and LOW for the pressed switch. Like this, try it,

const byte groundPin = 11;
const byte switchPin = 12;

void setup()
{
    Serial.begin(115200);
    pinMode(switchPin, INPUT_PULLUP);
    pinMode(groundPin, OUTPUT);
    digitalWrite(groundPin, LOW);
}

void loop()
{
  Serial.println(digitalRead(switchPin));
  delay(500);
}

That will be OK. Ground is ground. All of the ground pins are connected together.