iteration to recursive

Question

I have problems converting iteration to recursive function
this is the loop to convert:
https://code.sololearn.com/c6DOR5Btc93q/#cpp

this is what i have tried(it doesnt work):

double y (double x){
int n=256;
double o;
double a;
if(n>=2){
n=n/2;
o=x*x+(n/(x*x));
a=x*x+(n/o);
o=a;

y(x);

}
else return 1/o;

}

Answer 1

A S I thought you got an answer in your previous post itself, didn't you?

Answer 2

A S so are you approaching from top to bottom or bottom to top?

Answer 3

A S if you consider your x=16 then your y is coming out something around 0.003906 and this is just an approximation. It will vary for different values of x. Just wanted to let you know because I don't think you would have solved it on paper.

Answer 4

https://code.sololearn.com/c98i3E3327mz/?ref=app
I altered your code cause i think you make somthing wrong
And then i made it the way i would do the recursion

Answer 5

In the first recursion call z =1
So 1/(x*x + recursion (x*x, 2)) is returned. So with all the recursions the whole arithmetic expression is build up. z << 1 is the binary left shift with 1 which is equal to z * 2 because 2^1=2.
x*x is always the same so i save it in xpow.

Answer 6

@Avinesh i figured out how to do it with loop and now i need to convert to recursive :)

Answer 7

@Avinesh from bottom to top

Answer 8

double recursive(double x, double o, double n){
if(n<=1) return 1/o;
else {
o=x*x+(n/(x*x));
o=x*x+(n/o)
return recursive(x,o,n/2);
}
}

I didnt test it but maybe this works

Answer 9

When you dont make return statement to the recursive function call you cant get the output of the recurion

Answer 10

@Jnn oh yes i forgot about return :D

Answer 11

And why do you need a in your calculation, cause you only assing a with a value and after that pass this value to o, so why do you not pass it directly to o

Answer 12

@Jnn in your code o,a,x arguments are required but only x is provided(as you can see in my original loop). And it doesnt say to start dividing n from 256 in your code

Answer 13

because this is the original formula: https://imgur.com/pmJzAFV
i am using a and o to go from the bottom to the top by passing one to another

Answer 14

You cant initialize the start variable in the for loop cause that is used in every iteration

Answer 15

@Jnn thanks a lot!!
could you please explain this line?
return z/(xpow + recursion (xpow, z << 1));