Why Does My Java Code Convert an Integer to an Unprintable Character?

Converting Integer to Character in Java: A Comparison

Understanding character and integer conversions in Java can be tricky. Let's examine the following code snippets:

int a = 1;
char b = (char) a;
System.out.println(b);

Expectedly, this code should print the character '1'. However, it produces an empty output. To understand this, we need to delve deeper into the type conversion process.

The assignment char b = (char) a converts the integer a (which is the number 1) to a character. This conversion actually stores the character with the Unicode code point corresponding to the integer value. For example, the Unicode code point for '1' is 49, whereas the Unicode code point for the start-of-heading character is 1. Since the integer a is 1, it gets converted to the start-of-heading character, which is not printable.

In contrast, the following code snippet:

int a = '1';
char b = (char) a;
System.out.println(b);

Produces the expected output '1'. This is because the assignment int a = '1' initializes a with the ASCII value of '1' (which is 49) rather than the integer value 1.

To convert an integer to a character as intended in the first snippet, you can use the following approaches:

• Use the Character.forDigit() method: This converts a digit between 0 and 9 to its corresponding character.

  int a = 1;
  char b = Character.forDigit(a, 10);
  System.out.println(b); // Prints '1'

• Add 48 to the integer and cast: This approach relies on the fact that the Unicode code points for digits are 48 higher than the digit values.

  int a = 1;
  char b = (char) (a + 48);
  System.out.println(b); // Prints '1'

• Use the Character.toChars() method: This converts a Unicode code point to its corresponding character array.

  int a = 1;
  char[] b = Character.toChars(a);
  System.out.println(b[0]); // Prints '1'

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