Recursive functions or loop operators, which is faster or memory saving or both?

Question

Cycle operations

Answer 1

Loops should be more efficient than recursion. The reason:
- everytime a function is called, the parameters have to be saved on the stack before the function can be called
- when a function is called local variables have to be created on the stack
- when the function returns, the return value has to be put on the stack
- after a function call evaluate the return value

If you can programm everything in a loop, you will save a lot of variable creation and function calling.

Answer 2

What if it's not C++, what about Java or something like Javascript?, does it do the same thing?

Answer 3

In addition to that I think loops creates variables too and it's probably done on the stack memory.

Answer 4

#include <iostream>

using namespace std;

int main() {
int i, num1, num2, sum = 0;
num1 = 3;
num2 = 7;
for(i = num1; i <= num2; i++) {
sum += i;
cout << "This i = " << i << " and sum = " << sum << endl;
}
cout << "This i = " << i << " and sum = " << sum << endl;
return 0;
}
I think I've found out something, in the above code the output is:
This i = 3 and sum = 3,
This i = 4 and sum = 7,
This i = 5 and sum = 12,
This i = 6 and sum = 18,
This i = 7 and sum = 25,

and after exiting the loop operation,

This i = 8 and sum = 25.

This indicates that variables instantiated during operation still exists while in recursive functions they are deleted after function termination.

Answer 5

So just put Int i Info the for end it will gone after the loop. And you can scope the other variables. But that's not what I meant!

Answer 6

Now I get it, scope resolution stuff, int i is still withing the scope of the output

Answer 7

But that doesn't mean it's being deleted, now see this code in Javascript:

var i, num1, num2, sum = 0;
num1 = 3;
num2 = 7;
for(i = num1; i <= num2; i++) {
var intValue = i + (i * 2);
sum += i;
document.write("This i = " + i + " and sum = " + sum + "<br />");
}
document.write("This i = " + i + " and sum = " + sum + "<br />" + "intValue variable from loop operation = " + intValue + "<br />");

the thing is that it is obviously seen that in C++ any part of an expression/group of statements scope can be delimited withing braces { } in Javascript the variable is still accessed, the code will still be experimented in Java program and I'll get back to you.