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CONVERT STRING TO LONG INTEGER IN JAVA ALGORITHM HOW TO
CONVERT STRING TO LONG INTEGER IN JAVA ALGORITHM CODE
CONVERT STRING TO LONG INTEGER IN JAVA ALGORITHM PLUS

In Java 8, we can adjust the penultimate line of the above example as follows: int i = Integer.parseUnsignedInt(s, 16) Code language: Java ( java )Īs output, we don't see 3,405,691,582. These methods allow us to parse numbers in the range 0 to 4,294,967,295 (= 0xffffffff hexadecimal or 32 ones in the binary system).

int i = Integer.parseUnsignedInt(s, radix) (→ JavaDoc).

int i = Integer.parseUnsignedInt(s) (→ JavaDoc).

To make this work, after all, the language creators added the following methods to Java 8: Hexadecimally, this negative number is represented as the positive value "cafebabe", which in turn cannot be converted back by the parseInt() method. We see that hex contains the negative value -889,275,714 (I've inserted the thousands separators here for the sake of clarity). ( "i = " + i) Code language: Java ( java ) ( "hex binary = " + Integer.toBinaryString(hex)) Let's add some debug output to the code above: int hex = 0xCAFEBABE If it is 1, the number is negative (for details on negative numbers, see this Wikipedia article). In an int – which is always signed in Java – the first bit stands for the sign. Then why can we assign the number to the int variable hex? The binary representation of the numbers plays an (intended) trick on us. This number is higher than Integer.MAX_INT and therefore, cannot be represented as an int. If you convert "cafebabe" to the decimal system, you get 3,405,691,582. The reason is that the parseInt() method assumes the given number to be positive unless a minus sign precedes it. Why can't this String be converted back to an int? This attempt results in the following error: Exception in thread "main" : For input string: "cafebabe"įirst of all: The String s contains "cafebabe" as expected. Int i = Integer.parseInt(s, 16) Code language: Java ( java ) It becomes interesting (not to say: confusing) if, for example, we convert the valid int value 0xCAFEBABE into a hex String and then back into an int: int hex = 0xCAFEBABE In all the above cases, the number to be parsed must be within the range Integer.MIN_VALUE (= -2 31 = -2,147,483,648) to Integer.MAX_VALUE (= 2 31-1 = 2,147,483,647).

A hexadecimal number can be parsed as follows: The parameter radix specifies the base of the number system. Integer i = Integer.valueOf(s, radix) (→ JavaDoc).int i = Integer.parseInt(s, radix) (→ JavaDoc).To parse other number systems, the following overloaded methods are available: Integer.parseInt("1,000") // Thousands separator not allowed.Integer.parseInt("3.14") // Decimal point not allowed.Integer.parseInt(" 1") // Space not allowed.Integer.parseInt("") // Empty string not allowed.The following Strings are not allowed and result in NumberFormatExceptions:

CONVERT STRING TO LONG INTEGER IN JAVA ALGORITHM PLUS

The String to convert must contain only digits, optionally with a plus or minus sign in front. The second method internally calls the first method and converts the result to an Integer object. Integer i = Integer.valueOf(s) (→ JavaDoc).int i = Integer.parseInt(s) (→ JavaDoc).

Let's first look at the options to parse a String into an int (or Integer).

You can find the source code for this article in my GitHub repository. Today you will learn what to consider in the opposite direction, i.e., when parsing a String to an int. * This static inner class represents a single decimal digit.In the previous article, I showed you that "" + i is the fastest way to convert an int into a String in Java. * Maps a given internal representation of a digit character to its visual Private static final Digit bitIndexToDigitChainMaps = new Digit * Maps individual radices and bits to the numbers they represent in the Private static final StringBuilder STRING_BUILDER = * Caching a string builder in order to save some computation. * This class contains a method for converting long} values to unsigned It is much slower than, but it was fun to code:

CONVERT STRING TO LONG INTEGER IN JAVA ALGORITHM HOW TO

This one is a research attempt to find out how to convert long values as unsigned long integers to Strings.