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kgng97ccs
Joined: 02 Apr 2022 Posts: 97
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Using itoa() to convert an integer to ASCII characters |
Posted: Mon Jun 06, 2022 11:02 pm |
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I am using CCS C compiler v5.078 within MPLAB IDE v8.92.
I tried to convert a 16-bit integer to four ASCII characters with the following code: Code: | char ASCII_4ch[5];
unsigned int16 num_ui16;
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itoa(num_ui16, 16, ASCII_4ch);
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Results:
If num_ui16 = 2, ASCII_4ch[] = {"2", NULL, NULL, NULL, NULL}
If num_ui16 = 255, ASCII_4ch[] = {"F", "F", NULL, NULL, NULL}
If num_ui16 = 8107 (0x1FAB), ASCII_4ch[] = {"1", "F", "A", "B", NULL}
Is there any way to “right-justify” the ASCII characters such that they are always presented in four ASCII characters including leading zeros (if any), as follows?
If num_ui16 = 2, ASCII_4ch[] = {"0", "0", "0", "2", NULL}
If num_ui16 = 255, ASCII_4ch[] = {"0", "0", "F", "F", NULL}
If num_ui16 = 8107 (0x1FAB), ASCII_4ch[] = {"1", "F", "A", "B", NULL} — no change
I will appreciate any comments or suggestions. Thank you. |
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Ttelmah
Joined: 11 Mar 2010 Posts: 19552
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Posted: Tue Jun 07, 2022 12:04 am |
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Basic answer. No...
itoa is a standard C function, and does not do this.
In standard C, there would be a simple answer by using sprintf, to transfer
to a second string. This normally supports '-' as a format specifier to
right justify. Unfortunately this is a specifier that CCS lacks....
However, provided you don't mind leading zeros, there is a simple answer:
Code: |
char ASCII_4ch[5];
unsigned int16 num_ui16;
sprintf(ASCII_4ch, "%04X", num_ui16);
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sprintf's hexadecimal output, supports filling with leading zeros (04, instead
of 4 for the width specifier), so for your 255, you will get:
{"0", "0", "F", "F", NULL}
etc..
Hopefully this is OK.
If not, it can be done by moving the string using strlen to find how long
the number is, and adding leading spaces. Fiddly though... |
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kgng97ccs
Joined: 02 Apr 2022 Posts: 97
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Posted: Tue Jun 07, 2022 3:26 am |
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Thank you so much, Ttelmah.
Yes, the sprintf gives the exact results we are looking for (we need the leading zeros in character form).
We also have a need to put two 8-bit integers into a character array, and I tried, as an example, the following sprintf code: Code: | char ASCII_4ch[5];
sprintf(ASCII_4ch, "%02X", 0xC1);
sprintf(ASCII_4ch+2, "%02X", 0x34); |
The sprintf really helps. Result: ASCII_4ch[] = "C134"
Thanks again. |
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Ttelmah
Joined: 11 Mar 2010 Posts: 19552
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Posted: Tue Jun 07, 2022 4:46 am |
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Brilliant.
Glad it was what you wanted. |
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