recursion

[momotaro]

this fonction is supposed to print character by character am just wondring if I can do better

void PROMPT(char *T)
{
	int i = 0;

	if(*(T+i) != '\0')
	{
		printf("%c", *(T+i));
		i++;
	}
	else
		return;
	PROMPT(T+i);
}

[YarrOfDoom]

There is still some room for improvement.
Try going over this code line by line with some example input and see if you can find what is obsolete.
If you really can't find it, I could provide you with some more hints.

[momotaro]

I feel that there is something odd because its not beautiful :) but can't get it

[YarrOfDoom]

Well to me the code looks like a converted loop (replace if by while and remove everything starting from else and it would work, however I guess you want to keep it recursive here), so try thinking about something you would need in a loop, but not necessarily in a function.

[momotaro]

I know that that "i" is not a good idea but how do you wanna keep track of your position on the string??

[YarrOfDoom]

If you look closely at the code, you see that i only takes the values '0' and '1', because every time the function is called, it is initialised back to '0'.
So in this case, i can be replaced with constants throughout the code.

[momotaro]

the code become:


[CODE=C]

void PROMPT(char *T)
{
if(*T != '\0')
printf("%c", *T);
else
return;
PROMPT(T+1);
}[/CODE]

and it's working! thx

[Banfa]

Your printf could be replaced with putchar.

Where you recursively call PROMPT ask yourself under what condition you get there? There are 2 return points from this function, they could be reduced to 1.

[momotaro]

sorry but I don't see how

[Banfa]

The function has 2 execution paths when *T != '\0' and when *T == '\0'. It also has 1 explicit return (and i implicit return). Obviously you can not remove the implicit return so examine the 2 execution paths to see which statements get executed for the 2 conditions and see if you can simplify the 2 paths and reduce to a single implicit return.

As a clue you need an if without an else.

[momotaro]

void PROMPT(char *T)
{
	if(*T == '\0') 
		return;
	printf("%c", *T);
	PROMPT(T+1);	
}

thx!

[Banfa]

Not bad but reverse the if condition and you can remove the return statement too, you will need 1 each of these {, } too.

[momotaro]

perfect this is recursion ! thx

[weaknessforcats]

if(*T == '\0')

is the same as

if(!(*T))

so you get:

if(!(*T)) return;