Alternative to sprintf() to format the integer to an ascii character

Question

In my current program, I need to format an integer into an ASCII character. This will work with sprint() or snprintf().

Is there any alternative to sprintf() or snprintf() to format the data?

Thanks, Pavan.

You want to format it into exactly one character? Will the integer be between 0 and 9? — interjay, Jan 19 '15 at 13:57
@Thomas :I am writing an embedded program. Since usage of sprintf() will involve a large overhead. I need to avoid it. — Pavan Munavalli, Jan 19 '15 at 14:01
@sirlark: I can use itoa(). But is formatting possible with itoa() ? — Pavan Munavalli, Jan 19 '15 at 14:18
@Pavan what kind of formatting do you need, all itoa will give you is the integer as a decimal string — sirlark, Jan 19 '15 at 14:20
@sirlark: I need to display a decimal string as a character. For example if I have a decimal string of 65, I need to display as 'A'. But itoa() only helps me to convert an integer to a string. — Pavan Munavalli, Jan 19 '15 at 14:24
What about `chr(atoi(decimal_str))`? Also you might want to edit your question to make the types involved a little more clear — sirlark, Jan 19 '15 at 14:28

score 3 · Answer 1 · answered Jan 19 '15 at 13:58

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char ch = (char)(i + (int)'0'); /* Where i is an integer */

This works for 0 to 9

answered Jan 19 '15 at 13:58

Gopi

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the casting is unnecessary – David Haim Jan 19 '15 at 14:01
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@user3613500 Yes there will be implcicit conversions but just adds readability – Gopi Jan 19 '15 at 14:03
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The `(int)` cast is not needed. `'0'` is an `int`. No implicit conversion occurred. The `(char)` cast is reasonable to quell warnings. – chux - Reinstate Monica Jan 21 '15 at 23:57

score 1 · Answer 2 · answered Jan 19 '15 at 13:59

You could use any of *printf() functions, such as printf, s(n)printf, fprintf etc. *print**f** means "formatted printing". You might also try printf("%c",(char)65) but this might not help you very much. Built-in functions are in most cases faster than "self-written".

sirlark · Answer 3 · 2015-01-19T19:15:21.790

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The original question didn't make it clear that the input is a string containing an integer in decimal form, but reading the comments leads to a much lighter weight solution than sprintf

(char)(atoi(decimal_str))

Casting to char ensures the integer will be limited to 8 bits with the code of the same value. atoi converts a string of digits into an integer

edited Jan 19 '15 at 19:15

answered Jan 19 '15 at 17:48

sirlark

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Posted as an answer for future readers, so they don't have to dig through comments – sirlark Jan 19 '15 at 17:49
In what library/include file did you find this function `chr()`? It's not in any of the standard libraries. See also http://stackoverflow.com/questions/6405137/asc-and-chr-equivalent-in-c-c. – Jongware Jan 19 '15 at 18:33
Yes sorry, it's not standard. Confusion between turbo c and turbo pascal, in my foggy old memory. I've amended accordingly – sirlark Jan 19 '15 at 19:18

Alternative to sprintf() to format the integer to an ascii character

3 Answers3