How to see if numbers have same digits in array? - c

Question

I'm a bit stuck on one of my problems not because I don't know, but because I can't use more complex operations.(functions and multiple arrays)
So I need to make a program in C that ask for an input of an array(max 100 elements) and then program needs to sort that matrix by numbers with same digits.
So I made everything that I know, I tested my program with sorting algorithm from minimum to maximum values and it works, only thing that I can't understand is how should I test if the number have same digits inside the loop? (I can't use functions.)
So I know the method of finding if the number have the same digits but I don't know how to compare them. Here is an example of what I need.
This is what I have for now this sorts numbers from min to max.
#include <stdio.h>
int main() {
int matrix[100];
int i,j;
int temp,min;
int elements_number=0;
printf("Enter the values of matrix-max 100 elements-type -1 to end: ");
for(i=0;i<100;i++){
scanf("%d",&matrix[i]);
elements_number++;
if(matrix[i]==-1){
elements_number--;
break;
}
}
for (i=0; i<elements_number; i++) {
min=i;
for (j=i+1; j<elements_number; j++) {
if (matrix[j] < matrix[min])
min = j;
}
temp = matrix[i];
matrix[i] = matrix[min];
matrix[min] = temp;
}
for(i=0;i<elements_number;i++){
if(i!=elements_number-1){
printf("%d,",matrix[i]); }
else printf("%d.",matrix[i]);
}
return 0;
}
I need this output for these numbers:
INPUT :
1 22 43 444 51 16 7 8888 90 11 -1
OUTPUT:
1,22,444,7,8888,11,43,51,16,90.
Integers with 1 digit count as "numbers with same number of digits" like 7 and 1 in this example.
Hope that you can help.

Answer 1

After processing the array, the single-digit numbers should all be in the left part of the array, the other numbers in the right part. Within each part, the original order of the elements should be preserved. This is called a stable partition. It is different from sorting, because the elements are only classified into two groups. Sorting means that there is a clear relationship between any two elements in the array.
This can be done by "filtering" the array for single-digit numbers and storing the other numbers that were filtered out in a temporary second array. Then append the contents of that second array to the (now shorter) first array.
Here's how that could work:
#include <stdlib.h>
#include <stdio.h>
void print(const int *arr, int n)
{
for (int i = 0; i < 10; i++) {
if (i) printf(", ");
printf("%d", arr[i]);
}
puts(".");
}
int is_rep_digit(int n)
{
int q = n % 10;
n /= 10;
while (n) {
if (n % 10 != q) return 0;
n /= 10;
}
return 1;
}
int main()
{
int arr[10] = {1, 22, 43, 444, 51, 16, 7, 8888, 90, 11};
int aux[10]; // auxliary array for numbers with several digits
int i, j, k;
print(arr, 10);
j = 0; // number of single-digit numbers
k = 0; // number of other numbers
for (i = 0; i < 10; i++) {
if (is_rep_digit(arr[i])) {
arr[j++] = arr[i]; // pick single-digit number
} else {
aux[k++] = arr[i]; // copy other numbers to aux
}
}
k = 0;
while (j < 10) { // copy aux to end of array
arr[j++] = aux[k++];
}
print(arr, 10);
return 0;
}
Edit: I've just seen your requirement that you can't use functions. You could use Barmar's suggestion to test divisibility by 1, 11, 111 and so on. The tricky part is to find the correct divisor, however.
Anyway, the point I wanted to make here is that you don't need a full sorting algorithm here.