Q1. Write a C Program to print the duplicate elements of an array.

Question

In this program, you need to print the duplicate elements present in the array.

Answer 1

Certainly! Below is a simple C program that takes an array of integers, checks for duplicate elements, and prints them out.

#include <stdio.h>

int main() {
    int arr[100], n, i, j;
    int isDuplicate;

    // Read the size of the array
    printf("Enter the number of elements in the array: ");
    scanf("%d", &n);

    // Read the elements of the array
    printf("Enter the elements:\n");
    for(i = 0; i < n; i++) {
        scanf("%d", &arr[i]);
    }

    printf("Duplicate elements in the array are: ");
    int foundDuplicate = 0; // Flag to check if any duplicate has been found

    // Check for duplicate elements
    for(i = 0; i < n; i++) {
        isDuplicate = 0; // Reset duplicate flag for new element
        for(j = 0; j < i; j++) {
            if(arr[i] == arr[j]) {
                isDuplicate = 1; // Mark as a duplicate
                break;
            }
        }
        if(isDuplicate) {
            // Check if we've already printed this duplicate
            if (!foundDuplicate) {
                printf("%d ", arr[i]);
                foundDuplicate = 1; // Set the flag after finding the first duplicate
            }
        }
    }

    if (!foundDuplicate) {
        printf("No duplicates found.");
    }

    printf("\n");
    return 0;
}

Explanation:

1. Input Handling: The program starts by asking the user for the number of elements in the array and then reads the elements.
2. Duplicate Checking:
   • We use two nested loops to compare each element with the others before it.
   • If a duplicate is found, it checks if it has been printed before to avoid printing the same duplicate multiple times.
3. Output: Finally, it prints out the duplicate elements or states that none were found.

How to Compile and Run:

You can copy this code into a C file, say find_duplicates.c, then compile and run it using:

gcc find_duplicates.c -o find_duplicates
./find_duplicates

Make sure you have a C compiler like gcc installed on your system.