How to increment and decrement between two values

Question

This is embarrassing, but:

Let say I want to add 1 to x until it reaches 100. At that point I then want to subtract 1 from x until it reaches 1. Then I want to add 1 to x until it reaches 100, and so on.

Could someone provide some simple pseudocode to this question that is making me feel especially dumb.

Thanks :)

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EDIT 1

Apologies! I made my example too simple. I actually will be incrementing using a random number at each iteration, so responses that require (x == 100) would not work as x will surely go above 100 and below 1.

Answer 1

int ceiling = 100;
int floor = 1;
int x = 1;
int step = GetRandomNumber(); //assume this isn't 0

while(someArbitraryCuttoffOrAlwaysTrueIDK) {
    while(x + step <= ceiling) {
        x += step;
    }
    while(x - step >= floor) {
        x -= step;
    }
}

Or, being more concise (at the risk of being less clear):

while(someArbitraryCuttoffOrAlwaysTrueIDK) {
    while((step > 0  && x + step <= ceiling) || (step < 0 && x + step >= floor)) 
    {
        x += step;
    }
    step = step * -1;
}

Alternatively:

while(someArbitraryCuttoffOrAlwaysTrueIDK) {
    if((step > 0  && x + step > ceiling) || (step < 0 && x + step < floor)) 
    {
        step = step * -1;
    }
    x += step;
}