CODEWITHSUNDEEP
javacharascii
simplo
simplo

Reputation: 111

char[] into ascii and decimal value (double) java

based on this array :

final char[] charValue = { 'u', ' ', '}','+' };

i want to print the double value and the ascii value from it in Java. i can't find a proper solution for that in internet. I just found how to convert a single Character into Integer value. But what about many characters? the main problem is, i have a large char[] and some double and int values are stored in. for double values they are stored within 4 bytes size and integer 1 or 2 bytes so i have to read all this and convert into double or integer.

Thanks for you help

Upvotes: 0

Views: 1231

Answers (1)

Joop Eggen
Joop Eggen

Reputation: 109613

When java was designed, there was C char being used for binary bytes and text.

Java made a clear separation between binary data (byte[], InputStream/OutputStream) and Unicode text (char, String, Reader/Writer). Hence Java has full Unicode support. The binary data, byte[], need information: their used encoding, in order to be convertable to text: char[]/String.

In Java a char[] will rarely be used (as in C/C++), and it seems byte[] is intended, as you mention 4 elements to be used for an int etcetera. A char is 16 bits, containing UTF-16 text.

For this case one can use a ByteBuffer either wrapping a byte[] or being taken from a memory mapped file.

Writing

ByteBuffer buf = ByteBuffer.allocate(13); // 13 bytes
buf.order(ByteOrder.LITTLE_ENDIAN); // Intel order
buf.putInt(42);          // at 0
buf.putDouble(Math.PI);  // at 4
buf.put((byte) '0');     // at 12
buf.putDouble(4, 3.0);   // at 4 overwrite PI
byte[] bytes = buf.array();

Reading

ByteBuffer buf = ByteBuffer.wrap(bytes);
buf.order(ByteOrder.LITTLE_ENDIAN); // Intel order
int a = buf.getInt();
double b = buf.getDouble();
byte c = buf.get();

Upvotes: 1

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