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Math.PI

 
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. Given
double pi = Math.PI;
Which two are valid ways to round pi to an int?(Choose two.)
a) int p = pi;
b) int p = Math.round(pi);
c) int p = (int)Math.round(pi);
d) int p = (int)Math.min(pi + 0.5d);
e) int p = (int)Math.floor(pi + 0.5d);

correct answers are c and e .
can anyone explain wht does Math.PI do??
can anyone give a simple xample also??

regards
Kamal

 
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Math.PI=3.1415926.....
you should know how to pick info from JDK doc: http://java.sun.com/j2se/1.3/docs/api/java/lang/Math.html#PI
 
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pi is a mathematical constant(22/7) returned by Math.PI.
a) int p = pi;
pi is a double value, so it needs explicit casting into int narrowing conversion)
b) int p = Math.round(pi);
Math.round() returns a long value, so it needs explicit casting into int(narrowing conversion)
c) int p = (int)Math.round(pi);
explicit conversion to int done, hence correct
d) int p = (int)Math.min(pi + 0.5d);
Math.min takes 2 arguments and returns a double value, hence wrong
e) int p = (int)Math.floor(pi + 0.5d);
double value returned by Math.floor() converted to int hence correct
[This message has been edited by Sweekriti Engineer (edited March 21, 2001).]
 
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Thats a very good answer ... hope it has solved the doubt
 
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If you read the round() method in Math you will see that it uses the syntax shown in e to accomplish the rounding.
 
kamal jaisingh
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thx a lot all u guys u have replied,
now its clear to me abt math.pi.
thx again
regards
Kamal
 
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