# Decimal into binary numbers **URL:** \ **Category:** Beginners\ **Tags:** homework\ **Created:** [November 27, 2020, 3:25pm UTC](https://discourse.processing.org/t/decimal-into-binary-numbers/25758 "2020-11-27T15:25:02Z")\ **Posts on this page:** 3\ **Page:** 1

**Author:** ![Ellie98](https://avatars.discourse-cdn.com/v4/letter/e/e47774/32.png) [@Ellie98](https://discourse.processing.org/u/Ellie98)\ **Post date:** [November 27, 2020, 3:25pm UTC](https://discourse.processing.org/t/decimal-into-binary-numbers/25758/1 "2020-11-27T15:25:02Z")

Hey, i’m trying to convert the decimal numerbs into binary numbers but I get a lot of zeros in front of the binary numbers. How do I cut of the zeros? Thanks in advance! ```auto void setup() { //System.out.printf("Dez -> Dualzahl|\n"); for (int a = 0, b = 32, c = 64, d=96, e=128, f=160, g=192, h=224; a <=31; a++, b++, c++, d++, e++, f++, g++, h++) { System.out.printf("%3d ->\n", a, b, c, d, e, f, g, h); System.out.printf("" + binary(a)); } } ``` ---

**Author:** ![josephh](https://yyz2.discourse-cdn.com/flex036/user_avatar/discourse.processing.org/josephh/32/210_2.png) [@josephh](https://discourse.processing.org/u/josephh)\ **Post date:** [November 27, 2020, 7:05pm UTC](https://discourse.processing.org/t/decimal-into-binary-numbers/25758/2 "2020-11-27T19:05:06Z")

Hi, If you look at the [`binary()`](https://processing.org/reference/binary_.html) function, it’s returning the binary representation as a `String`. In order to get a portion of a `String` in Java, use the [`subtring()`](https://www.tutorialspoint.com/Java-String-substring-Method-example) method which takes to indices and return the corresponding substring. You can write a method to cut the first n characters of a String : ```java /* Cut the first n characters from a source String */ String trimCharacters(String source, int n) { return source.substring(n, source.length()); } ``` That you can use like this : ```auto println(trimCharacters(binary(a), 20)); ``` Note that it’s more coherent to use the pre defined `print()` and [`println()`](https://processing.org/reference/println_.html) functions in Processing rather than classic Java `System.out.print...` If you want to remove all the zeros, you need to compute the maximum exponent `p` where `2 to the power of p` is less than or equal to your number `a`, which represents the length of your binary number without the zeros. You can use another function to do this : ```auto /* Return the highest exponent p where 2**p < n */ int getHighestExponentPowerOfTwo(int n) { int p = 0; while (pow(2, p) < n) p++; return p; } ``` It increase a value `p` and stops when `2**p > n`. Since the `binary()` function returns the `32 bit` representation of the value, we need to cut `32 - binary size of a` zeros from the string. So finally it goes like this : ```auto // We add one because the smaller power start with 0 int binaryLength = getHighestExponentPowerOfTwo(a) + 1; int zerosToTrim = 32 - binaryLength; println(trimCharacters(binary(a), zerosToTrim)); ``` And you get : ```auto 0 1 10 011 100 0101 0110 0111 1000 01001 01010 01011 01100 01101 01110 01111 10000 010001 ... ``` Note, this is a bit over complicated but it’s a nice exercise and it introduce you to functions if you are not used to 😉 A better way would be to use the [`indexOf()`](https://beginnersbook.com/2013/12/java-string-indexof-method-example/) method to get the first position of a `1` in the binary representation and cut from that index. I let you do this part! ---

**Author:** ![GoToLoop](https://yyz2.discourse-cdn.com/flex036/user_avatar/discourse.processing.org/gotoloop/32/86_2.png) [@GoToLoop](https://discourse.processing.org/u/GoToLoop)\ **Post date:** [November 28, 2020, 6:40am UTC](https://discourse.processing.org/t/decimal-into-binary-numbers/25758/3 "2020-11-28T06:40:54Z")

> [@Ellie98](#): > > How do I cut off the zeros? Function **binary()** has a 2nd parameter where we can specify how many digits we need: > **[binary() / Reference](https://processing.org/reference/binary_.html)** > > Converts an int, byte, char, or color to a String containing the equivalent binary notation. For example, the color value produced by color(0, 102, 153, 25… We can combine that w/ Integer.**numberOfLeadingZeros()** in order to know how many digits to remove outta total max of 32 bits: [https://docs.Oracle.com/en/java/javase/11/docs/api/java.base/java/lang/Integer.html#numberOfLeadingZeros(int)](https://docs.Oracle.com/en/java/javase/11/docs/api/java.base/java/lang/Integer.html#numberOfLeadingZeros(int)) ```auto for (int i = 0; i < 05000; i += 32) { final int digits = max(1, Integer.SIZE - Integer.numberOfLeadingZeros(i)); println(i, TAB, binary(i, digits)); } exit(); ``` ```auto 0 0 32 100000 64 1000000 96 1100000 128 10000000 160 10100000 192 11000000 224 11100000 256 100000000 288 100100000 320 101000000 352 101100000 384 110000000 416 110100000 448 111000000 480 111100000 512 1000000000 544 1000100000 576 1001000000 608 1001100000 640 1010000000 672 1010100000 704 1011000000 736 1011100000 768 1100000000 800 1100100000 832 1101000000 864 1101100000 896 1110000000 928 1110100000 960 1111000000 992 1111100000 1024 10000000000 1056 10000100000 1088 10001000000 1120 10001100000 1152 10010000000 1184 10010100000 1216 10011000000 1248 10011100000 1280 10100000000 1312 10100100000 1344 10101000000 1376 10101100000 1408 10110000000 1440 10110100000 1472 10111000000 1504 10111100000 1536 11000000000 1568 11000100000 1600 11001000000 1632 11001100000 1664 11010000000 1696 11010100000 1728 11011000000 1760 11011100000 1792 11100000000 1824 11100100000 1856 11101000000 1888 11101100000 1920 11110000000 1952 11110100000 1984 11111000000 2016 11111100000 2048 100000000000 2080 100000100000 2112 100001000000 2144 100001100000 2176 100010000000 2208 100010100000 2240 100011000000 2272 100011100000 2304 100100000000 2336 100100100000 2368 100101000000 2400 100101100000 2432 100110000000 2464 100110100000 2496 100111000000 2528 100111100000 ```