C Exercises: Find the difference between the largest integer and the smallest integer created by 8 numbers from 0 to 9

Last update on September 19 2025 12:44:56 (UTC/GMT +8 hours)

Find difference between largest and smallest integers from digits

Write a C program to find the difference between the largest integer and the smallest integer, which are created by 8 numbers from 0 to 9. The number that can be rearranged shall start with 0 as in 00135668.

Input:
Data is a sequence of 8 numbers (digits from 0 to 9).
Output:
The difference between the largest integer and the smallest integer.

Sample Solution:

C Code:

#include<stdio.h>

int main() {
  int max_val, min_val, k, d, t;

  // Prompt user to input an integer created by 8 numbers (0 to 9)
  printf("Input an integer created by 8 numbers (0 to 9):\n");
  scanf("%d", &d);

  int i, j, s[8] = {0};

  // Extract individual digits and store them in array s
  for (i = 0; d != 0; i++) {
    s[i] = d % 10;
    d /= 10;
  }

  // Sort the digits in descending order
  for (i = 0; i < 8; i++) {
    for (j = 1; j + i < 8; j++) {
      if (s[j - 1] < s[j]) {
        t = s[j - 1];
        s[j - 1] = s[j];
        s[j] = t;
      }
    }
  }

  max_val = 0;

  // Construct the largest integer from sorted digits
  for (i = 0; i < 8; i++) {
    max_val *= 10;
    max_val += s[i];
  }

  // Reverse the order of digits in array s
  for (i = 0; i * 2 < 8; i++) {
    t = s[i];
    s[i] = s[7 - i];
    s[7 - i] = t;
  }

  min_val = 0;

  // Construct the smallest integer from reversed digits
  for (i = 0; i < 8; i++) {
    min_val *= 10;
    min_val += s[i];
  }

  // Calculate and display the difference between the largest and smallest integers
  printf("\nThe difference between the largest integer and the smallest integer.\n");
  printf("%d - %d = %d\n", max_val, min_val, max_val - min_val);

  return 0;
}

Sample Output:

Input an integer created by 8 numbers (0 to 9):
25346879

The difference between the largest integer and the smallest integer.
98765432 - 23456789 = 75308643

Flowchart:

For more Practice: Solve these Related Problems:

• Write a C program to rearrange 8 digits to form the maximum and minimum numbers and compute their difference.
• Write a C program to extract digits from an integer, sort them in both orders, and calculate the difference.
• Write a C program to use string manipulation to rearrange digits and find the difference between the largest and smallest numbers.
• Write a C program to implement a function that takes an 8-digit number and returns the difference between its maximum and minimum rearrangements.

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