can we convert integer into character

Question

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?

Answer 1

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.