I'm trying to convert a integer number to an array of chars without using String operations.
My attempt was:
int number = 12;
char[] test = Character.toChars(number);
for (char c : test)
System.out.println(c);
There is no output, and should give me:
'1'
'2'
How can I fix this? Thank you!
Try something like this:
int number = 12345;
char[] arr = new char[(int) (Math.log10(number) + 1)];
for (int i = arr.length - 1; i >= 0; i--) {
arr[i] = (char) ('0' + (number % 10));
number /= 10;
}
System.out.println(Arrays.toString(arr));
[1, 2, 3, 4, 5]
Note that floor(log10(n) + 1) returns the number of digits in n. Also, if you want to preserve your original number, create a copy and use that in the for-loop instead.
Also note that you might have to adapt the code above if you plan on also handling non-positive integers. The overall idea, however, should remain the same.
log10 works with doubles, and could therefore be subject to rounding errors in some implementations. This implies that there is a risk that the array won't be long enough to store all the characters in some cases. So this answer is not as good as an answer that just works with integers, strings and characters (like the other three answers here).
java.lang.Math.java.lang.Math say that the result will be within 1 ULP of the right answer. That's not good enough.char[] test = Integer.toString(number).toCharArray();
Extract each digit of the number, convert it into a character(by adding '0') and store them into a char array. Let us know what you have tried.
char is a UTF-16 code unit. That cannot change.
+1 for @arshajii's code log10(n) + 1 is something new for me as well. If you intend to use Vectors instead of arrays you can also follow this procedure(But the Vector has elements in reverse order) in which you never need to calculate the size of number itself
public static Vector<Character> convert(int i) {
Vector<Character> temp = new Vector<Character>();
while (i > 0) {
Character tempi = (char) ('0' + i % 10);
i = i / 10;
temp.add(tempi);
}
return temp;
}
Integer.toString()and the related methods.Stringoperations? In my long career, nobody has ever placed such a restriction on me.Character.toChars()method actually does. It "Converts the specified character (Unicode code point) to its UTF-16 representation stored in a char array." Itsintparameter specifies "a Unicode code point"