int inputPins[] = {2, 3, 4, 5}; // create an array of pins for switch inputs
int ledPins[] = {10, 11, 12, 13}; // create array of output pins for LEDs
void setup()
{
 for (int index = 0; index < 4; index++)
 {
 pinMode(ledPins[index], OUTPUT); // declare LED as output
 pinMode(inputPins[index], INPUT_PULLUP); // declare as input
 }
}
void loop() {
 for (int index = 0; index < 4; index++)
 {
 int val = digitalRead(inputPins[index]); // read input value
 if (val == LOW) // check if the switch is pressed
 {
 digitalWrite(ledPins[index], HIGH); // LED on if switch is pressed
 }
 else
 {
 digitalWrite(ledPins[index], LOW); // turn LED off
 }
 }
}