Convert a signed decimal to hex encoded with two's complement

Question

I need to encode a signed integer as hexadecimal using via the two's complement notation. For example I would like to convert e.g. -24375 to 0xffffa0c9. So far I have been working on the following lines: parseInt(-24375).toString(2) > "-101111100110111" This matches what Wolfram Alpha displays, but I am not sure how to get to the signed 24bit int representation of the number (ffffa0c9). I've worked out how to take the unsigned binary number and represent this as two's complement: ~ parseInt("101111100110111", 2) + 1 > -23475 but I am not sure get the binary representation of this number to convert to hex. Any ideas? JavaScript questions and answers, JavaScript questions pdf, JavaScript question bank, JavaScript questions and answers pdf, mcq on JavaScript pdf, JavaScript questions and solutions, JavaScript mcq Test , Interview JavaScript questions, JavaScript Questions for Interview, JavaScript MCQ (Multiple Choice Questions)

Answer 1

To create two's-compliment numbers of fixed size I've created factory method: function createToInt(size) { if (size < 2) { throw new Error('Minimum size is 2'); } else if (size > 64) { throw new Error('Maximum size is 64'); } // Determine value range const maxValue = (1 << (size - 1)) - 1; const minValue = -maxValue - 1; return (value) => { if (value > maxValue || value < minValue) { throw new Error(`Int${size} overflow`); } if (value < 0) { return (1 << size) + value; } else { return value; } }; } Now, to solve your question you can create functions toInt8, toInt16, toInt32, etc. And use it to convert JS numbers to two's compliment. Example with int8: const toInt8 = createToInt(8); '0x' + toInt8(-128).toString(16); // -> 0x80 '0x' + toInt8(127).toString(16); // -> 0x7f '0x' + toInt8(-1).toString(16); // -> 0xff // Values less then 16 should be padded '0x' + toInt8(10).toString(16).padStart(2, '0); // -> 0x0a