# Regarding int operations out of range

Vasudhaiv Naresh

Ranch Hand

Posts: 57

posted 9 years ago

Hi all,

I have encountered a strange piece of code whic goes like:

=============================================================

final long A = 24*60*60*1000*1000;

final long B = 24*60*60*10000;

System.out.println("A/B = "+A/B);

============================================================

This gives "5" as against the expected value of "1000".

Can anybody let me know how this "5" has come?

Thanks,

Naresh

I have encountered a strange piece of code whic goes like:

=============================================================

final long A = 24*60*60*1000*1000;

final long B = 24*60*60*10000;

System.out.println("A/B = "+A/B);

============================================================

This gives "5" as against the expected value of "1000".

Can anybody let me know how this "5" has come?

Thanks,

Naresh

Matt Russell

Ranch Hand

Posts: 165

Adeeb Abdul Karim

Greenhorn

Posts: 8

posted 9 years ago

MAX VALUE of Integer = 2147483647

MIN VALUE of Integer = -2147483648

Value of A as Integer = 86400000000, it is more than what an integer can hold. So it rotates the bits, so current value is

24 * 60 * 60 * 1000 * 1000 = 500654080, instead of 86400000000

A = 500654080

B = 864000000

A/B = 0, not 5 !

Reason : When the numbers are participating in arithmatic operations, it will be converted to the type with highest capacity. Here all the participants are of int type. Hence multiplication and division happens on int; the LHS accepts it since long is a bigger type than iint, but does not have any role in operations.

As Matt Caripto suggested if you give 1000L and 10000L respectively, the arithmatic opertions will work in long type and A will be able to hold the full value of 86400000000.

Because

MAX VALUE of Long = 9223372036854775807

MIN VALUE of Long = -9223372036854775808

Value of A as Long = 86400000000

A/B = 100 , not 1000!

MIN VALUE of Integer = -2147483648

Value of A as Integer = 86400000000, it is more than what an integer can hold. So it rotates the bits, so current value is

24 * 60 * 60 * 1000 * 1000 = 500654080, instead of 86400000000

A = 500654080

B = 864000000

A/B = 0, not 5 !

Reason : When the numbers are participating in arithmatic operations, it will be converted to the type with highest capacity. Here all the participants are of int type. Hence multiplication and division happens on int; the LHS accepts it since long is a bigger type than iint, but does not have any role in operations.

As Matt Caripto suggested if you give 1000L and 10000L respectively, the arithmatic opertions will work in long type and A will be able to hold the full value of 86400000000.

Because

MAX VALUE of Long = 9223372036854775807

MIN VALUE of Long = -9223372036854775808

Value of A as Long = 86400000000

A/B = 100 , not 1000!

�That which begins, also ends.�

Barry Gaunt

Ranch Hand

Posts: 7729

posted 9 years ago

Funny, I have seen this code in a book recently. "Java Puzzlers" by Joshua Bloch, et al. The answer was given, and explained, there too.

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