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can we convert integer into character

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java

we can convert character to an integer equivalent to the ASCII value of the same but can we do the reverse thing ie convert a given ASCII value to its character equivalent?

public String alphabets(int[] num)
{
char[] s = new char[num.length];
String str = new String();
for(int i=0; i< num.length; i++)
{   
    s[i] = 'A' + (char)(num[i]- 1);
    str += Character.toString(s[i]);
}
return str;         
}

shows possible lost of precision error ...

like image 622
higherDefender Avatar asked Mar 28 '10 16:03

higherDefender


2 Answers

To convert to/from:

int i = 65;
char c = (char)i;

char c = 'A';
int i = (int)c;
like image 188
Justin Ethier Avatar answered Sep 19 '22 23:09

Justin Ethier


The error is more complex than you would initially think, because it is actually the '+' operator that causes the "possible loss of precision error". The error can be resolved if the cast is moved:

s[i] = (char)('A' + (num[i]- 1));


Explanation
In the first bullet list of §5.6.2 Binary Numeric Promotion in the Java Language Specification it is stated that:

When an operator applies binary numeric promotion to a pair of operands [...] the following rules apply, in order, using widening conversion (§5.1.2) to convert operands as necessary:

  • If any of the operands is of a reference type, unboxing conversion (§5.1.8) is performed. Then:
  • If either operand is of type double, the other is converted to double.
  • Otherwise, if either operand is of type float, the other is converted to float.
  • Otherwise, if either operand is of type long, the other is converted to long.
  • Otherwise, both operands are converted to type int.

In the next bullet list it is stated that:

Binary numeric promotion is performed on the operands of certain operators:

  • The multiplicative operators *, / and % (§15.17)
  • The addition and subtraction operators for numeric types + and - (§15.18.2)
  • The numerical comparison operators , and >= (§15.20.1)
  • The numerical equality operators == and != (§15.21.1)
  • The integer bitwise operators &, ^, and | (§15.22.1)
  • In certain cases, the conditional operator ? : (§15.25)

In your case, that translates to:

s[i] = (int)'A' + (int)((char)(num[i] - (int)1));
hence the error.
like image 27
matsev Avatar answered Sep 19 '22 23:09

matsev