Need to make sure value is within 0-255

Question

This is probably really easy, but I'm lost on how to "make sure" it is in this range..

So basically we have class Color and many functions to implement from it.

this function I need is:

Effects: corrects a color value to be within 0-255 inclusive. If value is outside this range, adjusts to either 0 or 255, whichever is closer.

This is what I have so far:

static int correctValue(int value)
{
    if(value<0)
        value=0;
    if(value>255)
        value=255;
}

Sorry for such a simple question ;/

Answer 1

fair enough. but you missed the final return statement

static int correctValue(int value)
{
    if(value<0) return 0;
    if(value>255) return 255;
    return value;
}

Answer 2

Just return value at the bottom of your function after your ifs and you are good.

Answer 3

What you have will work fine. You just need to return value at the end of your function. If you want to make it more concise, you can use a ternary expression at the cost of a little bit of readability:

value = (value < MIN) ?
            MIN : (value > MAX) ?
                    MAX : value;

Where MIN is 0 and MAX is 255.

Answer 4

clamping is pretty easy using max and min:

value = std::min(255,std::max(0,value))

but your method should be correct also.

Answer 5

static int correctValue(int value) {
 int correctedValue;
 if (value < 0) {
        correctedValue = 0;
 } else if (value > 255) {
        correctedValue = 255;
 } else {
        correctedValue = value;
 }

 return correctedValue;

}

Answer 6

It's good. I'd recommend making a clamp function for re-usability:

template <typename T>
void clamp(T& pValue, const T& pMin, const T& pMax)
{
    pValue = std::min(std::max(pValue, pMin), pMax);
}

template <typename T>
T clamp_copy(T pValue, const T& pMin, const T& pMax)
{
    clamp(pValue, pMin, pMax);
    return pValue;
}

That gives you an in-place and copying clamp:

int i = 50;

j = clamp_copy(i, 0, 10);
k = clamp_copy(i, 100, 1000);
clamp(i, 0, 100);

// i = 50
// j = 10
// k = 100

Answer 7

I agree with the other answers, with one modification; this should be an else-if statement. There is no need to test if the value is over 255 if you already know it is less than 0

static unsigned char correctValue(int value)
{
    if(value<0) value=0;
    else if(value>255) value=255;
    return value;
}

Answer 8

Instead of using an int, use an unsigned char, the value will then be unable to go lower than 0 or higher than 255.