Question

Can anyone help me write a C function, itoa (which logically complements the atoi function)? Takes an integer and an empty char array, converts the integer into a string of ASCII characters which represent the integer, and stores it into the empty char array.

Answer 1

#include <stdio.h>
#include <stdlib.h>

int mkDigit( int number, int base, char* answer )
{
char characters[] = { "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ" };
int remainder, index;

if( number == 0 )
return( 0 );

remainder = number % base;
number /= base;

index = mkDigit( number, base, answer );
answer[ index ] = characters[ remainder ];
return( ++index );
}

int main( int argc, char *argv[] )
{
char answer[19];
int number = atoi( argv[1] );

mkDigit( number, 10, answer );
puts( answer );
return( 0 );
}