CODEWITHSUNDEEP
cdate
OrElse
OrElse

Reputation: 9959

How can I convert a (long) date into a readable format in C?

I am trying to convert an long date to a readable format as

void ConvertToDateTime(unsigned long dateTime, char *result)
{
    uint8_t day = dateTime % 100;
    uint8_t month = (dateTime / 100) % 100;
    uint8_t year = dateTime / 10000;

    sprintf(result,
            "%02u/%02u/%04u",
            day,
            month,
            year);
}

The caller method...

char *readableDateTime = (char*)"";
ConvertToDateTime(atoi(datestring), readableDateTime);

While debugging the datetime parameter is 20191112 (yyyymmdd) but the result is

null | empty string | nada if you prefer.

What am I doing wrong here?

Upvotes: 0

Views: 170

Answers (1)

Jonathan Leffler
Jonathan Leffler

Reputation: 753785

Your code writes to a 1-byte readonly area of memory. This is more likely to crash the program than do anything useful. Use:

char readableDateTime[100] = "";

Also, an 8-bit unsigned integer can only hold values 0..255. Note that 2019 % 256 is 227. Use at least uint16_t for year.

Upvotes: 1

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