method to convert a int into a binary format in C without itoa?

Question

how can i convert a integer with radix 10 to a binary string with C without having the itoa function?

An integer (`int`, etc.) _is_ in binary. Do you want to convert a string? — Chris Lutz, Mar 09 '11 at 21:55
Please give an example of what you're looking for, as your question isn't clear. — Oliver Charlesworth, Mar 09 '11 at 21:56
possible duplicate of [Is there a printf converter to print in binary format?](http://stackoverflow.com/questions/111928/is-there-a-printf-converter-to-print-in-binary-format) — Adam Rosenfield, Mar 09 '11 at 21:56
Example input and expected output would make everything about this question clear. — Edwin Buck, Mar 09 '11 at 21:58

score 0 · Accepted Answer · answered Mar 09 '11 at 22:00

0

You can print a '0' if the number is even or '1' if it is even, then divide by 2 and recurse. Only the other way around ... or something like that.

Example with 13

    13 is odd  so print 1 and divide by 2 giving 6
     6 is even so print 0 and divide by 2 giving 3
     3 is odd  so print 1 and divide by 2 giving 1
     1 is odd  so print 1 and divide by 2 giving 0
     0 reached so stop and read the printing backwards
             from this ^^^ column

13 is 1101 in binary

answered Mar 09 '11 at 22:00

pmg

106,608
13
126
198

1

Depending on architecture and compiler implementation, right-shift by one could be faster. (It certainly won't be slower.) – Cajunluke Mar 09 '11 at 22:08
It'll print in the right order if you recurse before printing. – Chris Lutz Mar 09 '11 at 22:14

method to convert a int into a binary format in C without itoa?

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