C Programming: Count unique digits of integers

C Programming Mathematics: Exercise-37 with Solution

Write a C program that counts the number of integers whose digits are unique from 1 and a given integer value.

Example:
Input: n = 30
From 1 to 30 all the integers have unique digits, except 11 and 22
Output: 28

Test Data:
(30) -> 28
(135) -> 110

Sample Solution:

C Code:

#include <stdio.h>
#include <math.h>

int test(int n) {
  //Length of an integer
  int len = floor(log10(abs(n))) + 1;
  int temp, i;
  int count = 0;
  int data[10] = {
    0
  };
  while (n > 0) {
    temp = n % 10;
    n = n / 10;
    data[temp]++;
  }
  for (i = 0; i < 10; ++i) {
    if (data[i] == 1)
      count++;
  }
  if (count == len)
    return len;
  else
    return 0;
}
int main(void) {
  int n = 135, ctr = 0, result;
  for (int i = 1; i <= n; i++) {
    result = test(i);
    if (result > 0) {
      //printf("\ni = %d, result = %d",i,result);
      ctr++;
      result = 0;
    }
  }
  printf("Unique digits of integers from 1 and %d = %d", n, ctr);
}

Sample Output:

Unique digits of integers from 1 and 135 = 110

Flowchart:

C Programming Code Editor:

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