How to Convert ASCII Code (0-255) to its Corresponding Character?

Unveiling ASCII and char

In Java, ASCII characters are represented within the char data type due to the convenience of char accepting a 16-bit Unicode character. ASCII, being a subset of Unicode, snugly fits within this range.

This process does not involve additional overhead of traversing tables or invoking methods; you're directly telling Java to interpret the integer as an ASCII value, leading to high-speed conversion.

Always remember, the ASCII series consists of control characters (0-31, 127), symbols and punctuation, and alphanumeric characters (32-126) that are part of the standard ASCII codes.

Behind the Scenes

Checking before Casting

Rushing in without validation can lead to mayhem. Ensure your conversion candidate lies between 0 to 255 before casting:

int asciiCode = 65;
if(asciiCode >= 0 && asciiCode <= 255) {
    char character = (char) asciiCode;
   // "Always check, before you wreck!" - Ancient coder proverb
}
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Playing within bounds ensures your code is more robust and error-proof.

Character to String Conversion

Need a string instead of a character? The Character.toString method and Java string concatenation come to the rescue:

String characterStr = Character.toString((char) asciiCode);
// or even simpler
String characterStr = "" + (char) asciiCode;
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Guess what? You now have more strings attached!

Handling Special Cases

Dealing with Unicode

For international characters beyond ASCII, Character.toChars method comes handy supporting all Unicode values:

int codePoint = 0x1F600; // Unicode code point for 😀
char[] charPair = Character.toChars(codePoint);
// "Who needs words, when there are Emojis!" - Modern coder proverb
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Character.toChars may return more than one element to represent a single character in a char array - Welcome to the world of surrogate pairs in UTF-16!

Crafting a String

Building a string from ASCII codes? Here is a neat trick:

char[] charArray = { 65, 66, 67 }; // 'A', 'B', 'C' or "ABC in disguise"
String str = new String(charArray);
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This string constructor transforms an array of integers into an ASCII character string - from numbers to letters!

Code Points to Strings

What if you want to create a string from code points directly? Java has got you covered:

int[] codePoints = { 65, 66, 67 }; // 'A', 'B', 'C'
String strFromCodePoints = new String(codePoints, 0, codePoints.length);
// "Building strings, one code point at a time!" - Builder coder proverb
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The String constructor can accept an array of code points and morph it into a string. This is a lifesaver when you are dealing with an array of ASCII or Unicode code points.