Question

Maybe my title is a little bit confusing so I’ll illustrate with a scenario

Let say I want to compare between 2 int values and return me a boolean based on the logical comparison.

if (int1 > int2) return true;
if (int3 < int4) return true;
if (int5 == int6) return true;
if (int7 >= int8) return true;
if (int9 <= int10) return true;

But instead of writing this manually, I wish to do something like

- (bool)compareVal1: (int)val1 withVal2: (int)val2 usingLogical: (NSString*)logic
{
     if (val1 "logic" val2) return true;
}

I want a general function which can be used to represent the 5 logical comparison that I want.
I’m not sure whether this is achievable but if you have any other solutions, please advise 🙂

Answer 1

Well first off, I would use an enum instead of an NSString to decide which logical operator to use. So try something like this:

typedef enum {

    GREATER_THAN,
    LESS_THAN,
    LESS_THAN_OR_EQUAL,
    GREATER_THAN_OR_EQUAL,
    EQUALS

} logicalOperator;    

And the actual function would look like this:

+ (bool)compareVal1: (int)val1 withVal2: (int)val2 usingLogical: (logicalOperator)op
{
    switch(op) {

        case GREATER_THAN:
            return (val1 > val2);

        case LESS_THAN:
            return (val1 < val2);

        case LESS_THAN_OR_EQUAL:
            return (val1 <= val2);

        case GREATER_THAN_OR_EQUAL:
            return (val1 >= val2);

        case EQUALS:
            return (val1 == val2);
    }
}

I would also make the function a static/class function because it does not truly affect a specific instance of a class, but rather it is a utility function that operates on the values passed in. An example of this functions usage would be this:

bool isGreater = [MyClass compareVal1: 4 withVal2: 3 usingLogical: GREATER_THAN];