Convert Hexa to Decimal in Swift

Question

I want to convert Hexa value into decimal. So I have tried this. When value is >0, then it is working fine. But when value is <0, then is returns wrong value.

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Answer 1

FF 88 is the hexadecimal representation of the 16-bit signed integer -120. You can create an unsigned integer first and then convert it to the signed counterpart with the same bit pattern:

let h3 = "FF88"
let u3 = UInt16(h3, radix: 16)!  // 65416
let s3 = Int16(bitPattern: u3)   // -120

Answer 2

Hexadecimal conversion depends on integer Type ( signed , unsigned ) and size ( 64 bits , 32 bits , 16 bits . . ) , this is what you missed .

source code :

let h3 = "FF88"
let d5 = Int16(truncatingBitPattern: strtoul(h3, nil, 16))
print(d5) // -120