convert an integer number into an array
I am trying to convert an integer number in C into an array containing each of that number's digits
i.e. if I have
int number = 5400
how can I get to
int numberArray[4]
where
numberArray[0] = 0;
numberArray[1] = 0;
numberArray[2] = 4;
numberArray[3] = 5;
Any suggestions gratefully received.
This would work for numbers >= 0
#include <math.h>
char * convertNumberIntoArray(unsigned int number) {
int length = (int)floor(log10((float)number)) + 1;
char * arr = new char[length];
int i = 0;
do {
arr[i] = number % 10;
number /= 10;
i++;
} while (number != 0);
return arr;
}
EDIT: Just a little bit more C style but more cryptic.
#include <math.h>
char * convertNumberIntoArray(unsigned int number) {
unsigned int length = (int)(log10((float)number)) + 1;
char * arr = (char *) malloc(length * sizeof(char)), * curr = arr;
do {
*curr++ = number % 10;
number /= 10;
} while (number != 0);
return arr;
}
Hint: Take a look at this earlier question "Sum of digits in C#". It explains how to extract the digits in the number using several methods, some relevant in C.
From Greg Hewgill's answer:
/* count number of digits */
int c = 0; /* digit position */
int n = number;
while (n != 0)
{
n /= 10;
c++;
}
int numberArray[c];
c = 0;
n = number;
/* extract each digit */
while (n != 0)
{
numberArray[c] = n % 10;
n /= 10;
c++;
}
You could calculate the number of digits in an integer with logarithm rather than a loop. Thus,
int * toArray(int number)
{
int n = log10(number) + 1;
int i;
int *numberArray = calloc(n, sizeof(int));
for ( i = 0; i < n; ++i, number /= 10 )
{
numberArray[i] = number % 10;
}
return numberArray;
}