function opposite to atoi()?

Question

I would like to convert an integer to a string like:

int a = 12345

coverts to

char b[6] = "12345"

basically the opposite of the atoi function that converts a string to an integer.

`char *t = s+sizeof(s) ; *--t = 0 ; do { *--t = (n % 10)+'0'; n/=10; } while (n);` (add a test for negatives) the string number is at `t`. — Déjà vu, Dec 09 '16 at 02:07

score 12 · Accepted Answer · edited Dec 09 '16 at 03:56

12

#include <stdio.h>
int sprintf(char *str, const char *format, ...);

Example

char str[10]; 
sprintf(str,"%d", 12345);

edited Dec 09 '16 at 03:56

chux - Reinstate Monica

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answered Dec 09 '16 at 01:58

vonzhou

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Thanks for the signature but how do you use it? – Déjà vu Dec 09 '16 at 01:59
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char str[10]; sprintf(str,"%d", 12345); – vonzhou Dec 09 '16 at 02:01

score 4 · Answer 2 · answered Dec 09 '16 at 02:00

source: Here

char * itoa ( int value, char * str, int base )

Convert integer to string (non-standard function) Converts an integer value to a null-terminated string using the specified base and stores the result in the array given by str parameter.

If base is 10 and value is negative, the resulting string is preceded with a minus sign (-). With any other base, value is always considered unsigned.

str should be an array long enough to contain any possible value: (sizeof(int)*8+1) for radix=2, i.e. 17 bytes in 16-bits platforms and 33 in 32-bits platforms.

But is not defined in ANSI-C and is not part of C++

A standard-compliant alternative for some cases may be sprintf:

sprintf(str,"%d",value) converts to decimal base.

Heatblast016 · Answer 3 · 2016-12-09T01:59:58.677

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Use itoa(). That should do the trick.(Only some compilers have it)

edited Dec 09 '16 at 01:59

answered Dec 09 '16 at 01:57

Heatblast016

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Not standard... – Déjà vu Dec 09 '16 at 01:57
@ringøwhat do you mean? – Heatblast016 Dec 09 '16 at 01:58
[This is what I mean](http://stackoverflow.com/questions/8257714/how-to-convert-an-int-to-string-in-c) – Déjà vu Dec 09 '16 at 01:58

function opposite to atoi()?

3 Answers3