for(i = 0; i<=timePassed; i  ) {
y = r * x * (1 - x)
System.out.println(y)

So how do I reset the value of y every time the for loop loops so that i can assign a new value to it? I cannot wrap my head around it I have already tried to set y to 0 at the end of the loop right after printing y but that didnt seem to work. I also tried setting it to null but that gave me an error(?) I cannot understand why this is happening can someone please explain how to do this and what I did wrong?

CodePudding user response：

Are you able to update your code block to include ALL code from your class.java file? It would help us see what could be wrong, because from this code snippet, y is not saved outside of the loop, therefore for every iteration (cycle) of the loop it would be reset and re-assigned.

As someone else has said, the y value does not change at any time in the loop, as all variables used (other than y) are declared outside of the loop. This loop simply prints the same y value "timePassed" amount of times.

CodePudding user response：

Here's the code that you posted, including line numbers:

1.  for(i = 0; i<=timePassed; i  ) {
2.  y = r * x * (1 - x)
3.  System.out.println(y)
4.

Here are various comments fixes:

• Line 1: assume i is declared somewhere, like this: int i
• Line 1: assume timePassed is declared somewhere and has a value set, like: int timePassed = 5;
• Line 2: assume y is declared somewhere, like: int y;
• Line 2: assume r and x are both declared somewhere, and have values set, like: int r = 1, x = 2;
• Lines 2-3: need semicolons to terminate each line inside the loop: add ; at the end of each line
• Line 4: add closing brace } to the "for" loop

Here is the code with those edits applied:

int timePassed = 5, y, r = 1, x = 2;
for (int i = 0; i <= timePassed; i  ) {
    y = r * x * (1 - x);
    System.out.println(y);
}

Running that code produces this output:

-2
-2
-2
-2
-2
-2

The output doesn't change. Why? Because the calculation to determine each new value of "y" is the same each time: r * x * (1 - x). Despite being inside a loop, and with i changing each iteration through the loop, i is not used in the calculation at all.

Here's an edit to the code, removing the entire "for" loop (and i), and it produces the same -2 value:

int y, r = 1, x = 2;
y = r * x * (1 - x);
System.out.println(y);

-2

To demonstrate that y is being set each time through the loop, here's a variation of the code (including output) where i is included in the calculation for y.

int timePassed = 5, y, r = 1, x = 2;
for (int i = 0; i <= timePassed; i  ) {
    y = r * x * (1 - x) * i;
    System.out.println(y);
}

0
-2
-4
-6
-8
-10