Dynamically set the initialization, condition, and in/decrementation of for-loops

Question

At the moment, I am having to write out multiple for-loops which all do the same task, with the differences being in the initialization, condition, and the de/incrementation within the for-loops themselves.

Here is an example of something similar I have so far:

if(some_bool_condition)
{
    for(int i = 0; i < 5; i++)
    {
        // do something
    }
} 
else
{
    for(int i = 10; i >= 5; i--)
    {
        // do same thing
    }
}

Is there a trick or technique I can use to merge these for-loops together?

Answer 1

int start = 0;  // or some other value
int end   = 5;  // ditto
int delta = 1;  // 1 or -1
for ( int i = start; i != end; i += delta )
{
    // do something
}

Of course the delta has to be choosen carefully so that i actually reaches end exactly.

Answer 2

Make do someting be a function. Pass the start value, test, and increment/decrement value as arguments. Do the for loop in the function.