Rotate object y-axis by 90 and -90?

Question

C++ / C#

The question is probably stupid. There is an object, it must rotate to the right by n degrees, then to the left.

float r = 90f;
float l = -90f;
float angle;
transform.Rotate(0, angle * Time.deltaTime, 0);

How to prescribe conditions so that when a rotation of, for example, 90 degrees is reached, the object will turn in the opposite direction by a certain number of degrees from the original angle?

Answer 1

int dur = 1;

//...

if (angle > 90) {
    dur = -dur;
}
float r = 90f;
float l = -90f;
float angle;
transform.Rotate(0, angle * Time.deltaTime * dur, 0);