C Program to Find the Second Smallest Element In an Array Without Sorting

🔍 C Program to Find the Second Smallest Element Without Sorting

#include<stdio.h>

int main()
{
    int num, a[100];
    printf("Enter the size of the array:\n");
    scanf("%d", &num);

    if (num < 2)
    {
        printf("Invalid input! At least two elements are required to find the second smallest element.\n");
        return 1;
    }

    printf("Enter %d elements:\n", num);
    for (int i = 0; i < num; i++)
    {
        scanf("%d", &a[i]);
    }

    int first, second;

    // Initialize first and second with the first two elements
    if (a[0] < a[1])
    {
        first = a[0];
        second = a[1];
    }
    else
    {
        first = a[1];
        second = a[0];
    }

    for (int i = 2; i < num; i++)
    {
        if (a[i] < first)
        {
            second = first;
            first = a[i];
        }
        else if (a[i] < second && a[i] != first)
        {
            second = a[i];
        }
    }

    if (first == second)
    {
        printf("All elements are equal.\n");
    }
    else
    {
        printf("The second smallest element in the array is %d\n", second);
    }

    return 0;
}
  

📝 Explanation:

This program finds the second smallest element without sorting the array. It maintains two variables, first and second, to track the smallest and second smallest values while iterating through the array.

💡 Sample Output:

Enter the size of the array:
6
Enter 6 elements:
4 2 8 5 1 3
The second smallest element in the array is 2
  

🔍 Keywords:

Second smallest number in array C, no sorting, min value tracking, C array programs, interview coding logic