## C# infinite Loops [closed] - c#

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Can someone help me understand why the loop below is infinite and how to make it finite?
int index = 1;
while (index != 10)
{
Console.WriteLine("Hello");
index += 2;
}
I tried putting it in Visual Studio but it did not run. I need to understand the logic. I am struggling with this course

It starts with index at 1 and increases by 2 (index += 2)
1
1 + 2
3
------:
-----:
3 + 2
5
------:
-----:
5 + 2
7
------:
-----:
7 + 2
9
------:
-----:
9 + 2
11
------:
-----:
11 + 2
13
Since you only stop at 10, it runs infinite.
(If you stop at >= 10, it will stop at 11)
Try using a debugger.

Visual studio will give you an error 'While' does not exist in the current context. Intellisense is your friend when learning a new language. Your error here is that While should be lower case while.
int index = 1;
while(index != 10)
{
Console.WriteLine("Hello");
index += 2;
}
Why is the loop infinite?
Set a breakpoint on the debugger to step through each line of the while loop. Hover over index to see it's new value upon each iteration. You'll see that your design only increments by odd numbers thus always satisfying your while condition index != 10.
There's many ways to make the loop finite. Start index at 0, or increment by one, or adjust your while condition. But I think the main thing from this question is that you need to brush up on c# syntax and VS intellesense\debugging. These tools will help you eleminate questions about the fundamentals of c#.

## Related

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for loops do not have an exit condition. They have a continue condition. When the middle condition is tested, the loop continues if it is true. x = 10 is an assignment expression. It assigns 10 to x, and the value of the assignment expression is the new value of x, so it is always 10 (or, if x is a _Bool, it is 1), which serves as “true” for the condition. You may have wanted x == 10, which is a comparison expression. But that is true only when x is 10, so the loop would never execute even the first iteration. You need to a condition to continue the loop, not to exit it, so you want x < 10.

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The expected result is 1.307. I think they are simply saying what the result of the calculation is, so you can check your answer.

The sequence you've got 1 + 1/2 - 1/3 + 1/4 + ... is the same as the Alternating Harmonic Series on Wikipedia, except with the signs from 1/2 onwards flipped: 1 - 1/2 + 1/3 - 1/4 + ... = ln 2 and the natural logarithm of 2, ln 2, = 0.693. Hence your 1.307 here = 2 - ln 2.

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