Computer Science Canada Random numbers |
| Author: | Neo [ Tue Nov 02, 2004 11:12 pm ] | ||||
| Post subject: | Random numbers | ||||
Hello, I am very noobish in Java so I need some help. I read my notes an there is a function Math.random to generate random numbers between 0.0 and 1.0. I want to generate an integer between 1 and 6. I looked around on the internet and found this code
I also messed arounnd with it a bit and chagned it to
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| Author: | wtd [ Tue Nov 02, 2004 11:19 pm ] |
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You want to look at the Java API docs for the Math class. For the random method, go to: http://java.sun.com/j2se/1.4.2/docs/api/java/lang/Math.html#random() The Math.random() functions returns a double. This is a floating point number between 0 and 1.0. To get that range to be 0 to 6, we simply multiply the result of it by 6, then convert it to an integer (disposing of everything after the decimal point. Of course, this will give us a number between 0 and 6, but it won't include 6. To do this, we simply add 1 and bump any random number generated up by 1. |
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| Author: | Neo [ Wed Nov 03, 2004 2:21 pm ] |
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wtd wrote: You want to look at the Java API docs for the Math class.
For the random method, go to: http://java.sun.com/j2se/1.4.2/docs/api/java/lang/Math.html#random() The Math.random() functions returns a double. This is a floating point number between 0 and 1.0. To get that range to be 0 to 6, we simply multiply the result of it by 6, then convert it to an integer (disposing of everything after the decimal point. Of course, this will give us a number between 0 and 6, but it won't include 6. To do this, we simply add 1 and bump any random number generated up by 1. If we bump up every number by 1 would it not be impossible to get 0? and when we convert a double into an int is the number rounded up or down or no rounding at all? and last question so would that code i typed in generate a random number from 1 to 6? |
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| Author: | wtd [ Wed Nov 03, 2004 2:58 pm ] |
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Neo wrote: wtd wrote: You want to look at the Java API docs for the Math class.
For the random method, go to: http://java.sun.com/j2se/1.4.2/docs/api/java/lang/Math.html#random() The Math.random() functions returns a double. This is a floating point number between 0 and 1.0. To get that range to be 0 to 6, we simply multiply the result of it by 6, then convert it to an integer (disposing of everything after the decimal point. Of course, this will give us a number between 0 and 6, but it won't include 6. To do this, we simply add 1 and bump any random number generated up by 1. If we bump up every number by 1 would it not be impossible to get 0? Yes. To get a number between 0 and 6, including 6, multiply by 7. Neo wrote: and when we convert a double into an int is the number rounded up or down or no rounding at all?
It simply discards everything after the decimal point. Neo wrote: and last question so would that code i typed in generate a random number from 1 to 6?
Yes. |
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