[SOLVED] HEX to DEC conversion

Projects Programming
1

Hi there,

I'm trying to convert Hexadecimal to Decimal number, but I have some issues with my formula.

Sometimes of HEX (8 chars) I got DEC as (9 chars), but I always need to get 10 DEC chars.

Example input:

A041FD73 = 2688679283 (good)
22D9B634 = 584693300  (wrong)

Formula:

uint8_t uid[16] = {0};
unsigned long decRes = 0;

for (uint8_t i = 0; i < 4; i++) {
 decRes <<= 8;
 decRes += uid[i];
}

Serial.println(decRes);

Thank you,

Kind regards,
Viktor

2

Take a look at this.

3

0x22D9B634 is indeed 584693300.
And 0x000000010 is 16, just 2 digits.

Your code is correct. You can't have 10 digits if your number is less than 10¹¹.
You can pad your number with zeros.

4

yfuq:
0x22D9B634 is indeed 584693300.
And 0x000000010 is 16, just 2 digits.

Your code is correct. You can't have 10 digits if your number is less than 10¹¹.
You can pad your number with zeros.

Starting or ending zero to add?

I must to follow NFC RFID standard.

Thank you!

5

looks like you just want a 10 digit string for display

results from following code

2688679283
0584693300

unsigned long  a = 0xA041FD73;
unsigned long  b = 0x22D9B634;

char s [40];

void setup (void) {
    Serial.begin (115200);

    sprintf (s, "%010lu", a);
    Serial.println (s);

    sprintf (s, "%010lu", b);
    Serial.println (s);
}

void loop (void) {}
6

gcjr:

sprintf (s, "%010lu", a);

Your example solved everything, thank you! :wink: