Simplifying conditionals

My job requires me to work in RPG, an old, old language. Worse yet I cannot use the free keyword because of our pre-processor, and I don't see that changing for some time.

With that in mind, I show you what I have learned when working with conditionals (specifically if).

Let's first assume that lowercase are boolean expressions and that uppercase are sets of statements and expressions (i.e., code instructions). Next I present some snippets, following a demonstration on how to simplify them.

Note: Ignore the brackets. I only use then to make clear where code breaks.

Case 1

	if(a)
	{
	if(b)
	{
	A
	}
	}

view raw conds_case1.c hosted with ❤ by GitHub

Simplification:

	if(a && b)
	{
	A
	}

view raw conds_case1_simple.c hosted with ❤ by GitHub

Case 2

Yes, I do find many of these:

	if(a)
	{
	A
	}
	if(b)
	{
	A
	}

view raw conds_case2.c hosted with ❤ by GitHub

Simplification:

	if(a || b)
	{
	A
	}

view raw conds_case2_simple.c hosted with ❤ by GitHub

Case 3

	if(a)
	{
	if(b)
	{
	B
	}
	}
	else
	{
	A
	}

view raw conds_case3.c hosted with ❤ by GitHub

Intermediate step:

	if(!a) // we reverse the order of the condition
	{
	A
	}
	else
	{
	if(b)
	{
	B
	}
	}

view raw conds_case3_intermediate.c hosted with ❤ by GitHub

Simplification:

	if(!a)
	{
	A
	}
	else if(b) // it's the exact same code, but with better identation
	{
	B
	}

view raw conds_case3_simple.c hosted with ❤ by GitHub

To some people this can seem quite obvious, but I find that most people don't bother to apply these rules, which gives readability a punch in the face.