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about switch case

 
Ranch Hand
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one question i had about the switch case is that why it does not allowed float double and long in the switch case ?what's the actual reason behind this?
 
Greenhorn
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The switch can hold a variable of an int compatibls primitive.
 
jinesh parikh
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Prasanna Vazza

thats what i am asking why they had made compulsory in switch case that switch expression must be of the type integer?
 
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Probably because comparing floating point values for equality is problematical. Floating point values are usually compared to be within a small range of each other, say 0.0000001. Exact equality is not really achievable at all possible values a floating point number can have.
 
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Hi.

Comparing floating-point numbers may lead to imprecision. In fact, this is probably a common rule in programming languages (well, at least in C++), because floating-point numbers are ruled by an IEEE (754) standard.
 
jinesh parikh
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Dear barry

can you give me any example of your statement please.......

because i am somewhat confused in your reply.
 
Rancher
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See #20 here for an introduction on floating point numbers, and a discussion of how they are imprecise. Specifically, with FP numbers the value "1.0" is not always equal to itself when it should be, e.g. 1.0 != 2.0/3.0 + 1.0/3.0.
 
jinesh parikh
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Dear Ulf Dittmer,

Thank you very much for your reply

Now i understood why it was not allowed to use the floating points in the switch case expression.

my next question is this was for floating points but whats wrong with long data type as it was also not allowed in switch case expression.
 
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