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# Problems calculating 2^n with For loop

Greenhorn
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I am trying to calculate 2^n with a for loop and am having some difficulties. My program uses a loop to generate numbers 1-20 which are then used to be n.
So if n = 3 (2^3) it should calculate 2*2*2, if n = 5 (2^5) it should calculate 2*2*2*2*2. But it does not do that, not sure what it does. It's the method all the way on the bottom that is giving me a hard time. Can someone help?

Sheriff
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Silke Sewell wrote:...not sure what it does. It's the method all the way on the bottom...

Welcome to the ranch!

To see what your method is actually doing, add some println statements. For example...

This should show you where it's going wrong.

Ranch Hand
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Hi Silke,

Welcome to Java Ranch

In the exponent method

why have you assigned also verify your loop within exponent which executes n+1 times.

Regards,
Antany.

Silke Sewell
Greenhorn
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marc weber wrote:

Silke Sewell wrote:...not sure what it does. It's the method all the way on the bottom...

Welcome to the ranch!

To see what your method is actually doing, add some println statements. For example...

This should show you where it's going wrong.

Thank you I have been trying to figure out a way to debug in JGrasp this helped. I got it fixed.

marc weber
Sheriff
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Since these are powers of 2, a nice exercise would be to code this using bit shifting instead of a for loop.

Bartender
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by the way, this too looks wrong to me:

isnt it same as :

I am not looking at the logic though, its just an observation.