C++ program for finding the second smallest element in an array

October 6, 2022

Second smallest element in an array in C++

Second Smallest Element in an array in C++

Here, in this page we will discuss the program to find the second smallest element in an array in C++ programming language. We are given with an array and need to print the second smallest element among them.

While loop in C

Here, in this page we will discuss the following methods to find the second smallest element of the array.

  • Method 1: Uses two loops find second smallest
  • Method 2: Using a single loop to find second smallest

Method 1 :

  • Declare a variable say smallest = arr[0], that variable hold the first minimum value of the array.
  • Run a loop and check if(arr[i]<smallest) then set smallest = arr[i].
  • Now, take a variable say sec_smallest = INT_MAX
  • Now, run a loop over the array, and check
  • If(arr[i]!=smallest && arr[i] < sec_smallest), then set sec_smallest = arr[i]
  • At last Print(sec_smallest)

Method 1 Code in C++

Run 
#include<bits/stdc++.h>
using namespace std;

int secSmallest(int arr[], int n)
{
   // assigning first element as smallest temporarily
   int smallest = arr[0];

   // we find the smallest element here
   for (int i=0; i < n; i++){
     if(arr[i] < smallest)
       smallest = arr[i];
   }

   // temporarily assinging largest max value
   int sec_smallest = INT_MAX;

   // finding second smallest here
   for (int i=0; i < n; i++){
      if(arr[i] != smallest && arr[i] < sec_smallest)
        sec_smallest = arr[i];
   }

   return sec_smallest;

}
int main()
{
    int arr[] = {70, 40, 30, 20, 10, 90};

    int n = sizeof(arr)/sizeof(arr[0]); 

    cout<<secSmallest(arr, n);
}

Output

20
 

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Method 2 :

  • Take Two variables say first = INT_MAX and second = INT_MAX to hold the first and second smallest elements respectively.
  • Run a loop to iterate over the entire array.
  • Check if (arr[i]<first) then set second = first and first = arr[i].
  • Else check if(second > arr[i]) then set second = arr[i]
  • After complete iteration print second.
Second smallest element

Method 2 Code in C++

Run 
#include<bits/stdc++.h>
using namespace std;

int main(){

   int arr[] ={ 90, 78, 67, 56, 7, 61, 10};
   int n = sizeof(arr)/sizeof(arr[0]);

   int first = INT_MAX, second = INT_MAX;

   for(int i=0; i<n; i++){
       if(arr[i] < first){ second = first; first = arr[i]; } else if(second>arr[i])
           second = arr[i];
    }

    cout<<second;
}

Output

10

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While loop in C