Develop Reference

"The literal 0008 of type int is out of range" [duplicate]

I am trying to write following code.but it gives me error kindly help me.
int six=06;
int seven=07;
int abc=018;
int nine=011;
System.out.println("Octal 011 ="+nine);
System.out.println("octal O18 =" + abc);
why i cant give 018 and 019 to variable.i can give value 020 and 021 to variable.
Why this happen? what's the reason behind this Kindly tell me.
I got Following error
integer number too large: 018
int eight=018;

Octal is base-8 number system, so it means digit can be from 0 to 7, you can't use digit 8 (and 9 too) in octal number system.

// Decimal declaration and possible chars are [0-9]
int decimal = 495;
// HexaDecimal declaration starts with 0X or 0x and possible chars are [0-9A-Fa-f]
int hexa = 0X1EF;
// Octal declaration starts with 0 and possible chars are [0-7]
int octal = 0757;
// Binary representation starts with 0B or 0b and possible chars are [0-1]
int binary = 0b111101111;
If the number is string format then you can convert it into int using the below
String text = "0b111101111";
int value = text.toLowerCase().startsWith("0b") ? Integer.parseInt(text.substring(2), 2)
: Integer.decode(text);

why i cant give 018 and 019 to variable.
Because an integer literal prefixed with 0 is treated as octal, and '8' and '9' aren't valid octal digits.
From section 3.10.1 of the JLS:
An octal numeral consists of an ASCII digit 0 followed by one or more of the ASCII digits 0 through 7 interspersed with underscores, and can represent a positive, zero, or negative integer.
Trying to use '8' in an octal number is like trying to use 'G' in hex... it's simple not part of the set of symbols used in that base.

Octal numbers (base 8) can only use the following figures: 01234567. The same way that decimal numbers (base 10) can only use 0123456789.
So in octal representation, 17 + 1 is 20.

The prefix 0 indicates octal(8 base)(digits 0-7).
public class MainClass{
public static void main(String[] argv){
int intValue = 034; // 28 in decimal
int six = 06; // Equal to decimal 6
int seven = 07; // Equal to decimal 7
int eight = 010; // Equal to decimal 8
int nine = 011; // Equal to decimal 9
System.out.println("Octal 010 = " + eight);
}
}

why i cant give 018 and 019 to variable.i can give value 020 and 021 to variable.
The leading zero signifies an octal literal. However, 8 and 9 are not valid octal digits. This makes 018 and 019 invalid.

When an integer literal starts with 0 in Java, it's assumed to be in octal notation. The digits 8 and 9 are illegal in octal—the digits can range only between 0 and 7.

Because it's octal, an octal number has 8 digits which spans from 0 to 7 inclusive. For the same reason 12 would be an invalid binary number.
You need at least base 9 to have 18 and a normal decimal base for 19.

For your query.....you assign an invalid value to the variable....your assigned value is started with 0(zero) ..which means that you are assigning an octal value to the variable and when you assign a value higher then 7 such as 018 in your case...the value excedes the range of octal variables and hence show an error...so try entering simply 18 so it would take it as an integer rather than an octal variable data type...

Trying to print a casted array of ints into chars,but I get message "integer number too large" [duplicate]

This prints 83
System.out.println(0123)
However this prints 123
System.out.println(123)
Why does it work that way?

A leading zero denotes that the literal is expressed using octal (a base-8 number).
0123 can be converted by doing (1 * 8 * 8) + (2 * 8) + (3), which equals 83 in decimal.
For some reason, octal floats are not available.
Just don't use the leading zero if you don't intend the literal to be expressed in octal.
There is also a 0x prefix which denotes that the literal is expressed in hexadecimal (base 16).

Because integer literals starting with 0 are treated as octal numbers.
See section 3.10.1 of the JLS

Try this:
public static String leftPad(int n, int padding) {
return String.format("%0" + padding + "d", n);
}
leftPad(5, 3); // return "005"
leftPad(15, 5); // return "00015"
leftPad(224, 3); // return "224"
leftPad(0, 4); // return "0000"

first one printed as 83 because java takes 0123 as octal number and it prints decimal equivalent of that number.

The octal (leading 0) and hexadecimal (leading 0x) were inherited from C.
For comparison, try
System.out.println(0x123);

In Java integer literals with a leading zero are octal integers (base 8).
(1 * 8^2) + (2 * 8^1) + (3 * 8^0) = 83
So do not use any number leading with 0 if you don't want to treat it as an octal number.

0123 -> 83
1010L -> 1010
0101L -> 65
The numbers 1010L and 0101L are not in binary representation (just to avoid the confusion).
These numbers are in decimal representation.
Even as per the Regex patterns in Oracle docs,
\0n is the character with octal value 0n (0 <= n <= 7)
\xhh is the character with hexadecimal value 0xhh
Thus, your number 0101 be it in Integer or Long format is treated as an Octal representation of a number.
123 => 1 * 8^2 + 2 * 8^1 + 1 * 8^0 = 83
0101 => 1 * 8^2 + 0 * 8^1 + 1 * 8^0 = 64 + 0 + 1 = 65

printf will do it: http://java.sun.com/developer/technicalArticles/Programming/sprintf/
public class X
{
public static void main(final String[] argv)
{
System.out.printf("%04d", 123);
System.out.println();
}
}
You could also make it "%0" + size + "%d" if you wanted to vary the length... though if the lengths were common I'd probably make constants like "%04d", "%012d", etc...

Unexpected int/Integer behavior when number starts by 0

I can't understand why this is not printing the expected value (400300) when I put extra zeros in front of the number:
System.out.println(new Integer(0400300)); // prints 131264
System.out.println(0400300); // prints 131264
If I put one or more zeros in front of the number, the expected value is not printed.
// JUnit test does not pass:
assertTrue(0400300 == 400300); // returns false!?

Adding 0 to the front made the number an Octal literal. So:
0400300 = 3 * 8 ^ 2 + 4 * 8 ^ 5 = 131264
See JLS for the relevant sections. Quote:
An octal numeral consists of an ASCII digit 0 followed by one or more of the ASCII digits 0 through 7 interspersed with underscores, and can represent a positive, zero, or negative integer.

integer assigning in java

public class Example {
public static void main(String args[]) {
int a = 0153;
int b=a;
System.out.println(""+b);
}
}
Can someone explain why it prints 107 and not 153?

Octal of 107 is 0153
In Java you can create octal literals simply by adding a leading zero like this: int a = 0755; Be careful! It is very common to specify an octal literal

Because a number starting by 0 is considered as an octal value in Java. 0153 in octal is 107 in decimal.

You write as octal and print defaults to decimal.
Input Prints (decimal)
Decimal 153 153
^
No leading zero (digits 0-9)
Octal 0153 107
^
leading zero (digits 0-7)
Hex 0x153 339
^^
leading 0x (digits 0-F)

How do I convert a decimal fraction to binary in Java?

I need to convert 0.5 in base 10 to base 2 (0.1).
I have tried using
Double.doubleToRawLongBits(0.5)
and it returns 4602678819172646912 which I guess is in hex, but it does not make sense to me.

No. 4602678819172646912 is in dec, hex is 0x3fe0000000000000. To dismantle that:
3 | F | E | 0 ...
0 0 1 1 1 1 1 1 1 1 1 0 0 ...
s| exponent | mantissa
s is the sign bit, exponent is the exponent shifted by 2^9 (hence this exponent means -1), mantissa is the xxx part of the number 1.xxx (1. is implied). Therefore, this number is 1.000...*2^-1, which is 0.5.
Note that this describes the "normal" numbers only, so no zeros, denormals, NaNs or infinities

Multiply you number by 2^n, convert to an BigInteger, convert to binary String, add a decimal point at position n (from right to left).
Example (quick & ++dirty):
private static String convert(double number) {
int n = 10; // constant?
BigDecimal bd = new BigDecimal(number);
BigDecimal mult = new BigDecimal(2).pow(n);
bd = bd.multiply(mult);
BigInteger bi = bd.toBigInteger();
StringBuilder str = new StringBuilder(bi.toString(2));
while (str.length() < n+1) { // +1 for leading zero
str.insert(0, "0");
}
str.insert(str.length()-n, ".");
return str.toString();
}

This is decimal for 0x3FE0_0000_0000_0000. The mantissa is the list of zeros after 3FE (which codes sign and exponent). This is what you are looking for, given that 0.1 before the zeros is implicit.

Do you want to convert the decimal string to floating-point binary or to a binary string? If the former, just use valueOf(); if the latter, use valueOf() followed by toString() or printf().

0.1 is NOT a binary representation of 0.5
Java will represent 0.5 using IEEE 754, as specified on the Java Language Specification. BigInteger.valueOf(Double.doubleToRawLongBits(0.5)).toByteArray() will give you a byte per byte representation of 0.5 as Java does internally.