lrint()

[Math]

long lrint(double x);

Description

Returns the value of x rounded to the nearest integer value, rounding halfway cases to the even integer value.

Parameters

x: The value to calculate the rounded value.

Returns

The value of x rounded to the nearest integer value as a long number.

Example Code

The code reads the value of a potentiometer connected to pin IN and places the rounded value of x on pin OUT.

void setup() {
    pinLabel(0, "IN");   // set the label of pin 0 to "IN"
    pinLabel(1, "OUT");  // set the label of pin 1 to "OUT"
    pinMode(1, OUTPUT);  // set pin 1 as output
    pinLabel(2, "VCC");  // set the label of pin 2 to "VCC"
    powerPin(2);         // set pin 2 as power pin
    pinLabel(3, "GND");  // set the label of pin 3 to "GND"
    groundPin(3);        // set pin 3 as ground pin
}
void loop() {   
    int val = analogRead(0); // read the value of the potentiometer   
    double x = map(val, 0, 1023, -5, 5); // map the value
    long y = lrint(x); // calculate the rounded value of x   
    int pwm = (int) map(y, -5, 5, 0, 1023); // map the value
    analogWrite(1, pwm); // write the value of pwm to pin 1
}

Notes and Warnings

If x is not a finite number or an overflow occurs, this function returns the LONG_MIN value (0x80000000).