Question

1. Create an array of ints with 20 elements. With a random number generator, seeded with time, assign a random number between 1 and 100 to each element of the array. Using the selection sort algorithm discussed in class, sort the array from smallest to largest. The sorting of the array should be done inside a user defined function. This function should not return any values to main using a return statement. It should have the following parameters: the array, and the number of elements in the array. Only the sorting should be done in the function. Everything else (including the random number generation, the printing of pre-sorted array, and the printing of the post-sorted array) should be executed in main. Print to the screen the array in a single line before it is sorted. Print to the screen the array in a single line after it is sorted. Sample output on a similar problem with a 5 element array is: Original array 36 47 54 82 15 Sorted array 15 36 47 54 82

Answer 1

Answer:

#include <iostream>

#include<time.h>

using namespace std;

void sort(int a[20],int n)   //selection sort

{

   int i,j,temp;

   for(i=0;i<n;i++)        

   {

       for(j=i+1;j<n;j++)  //finds minimum element

       {

           if(a[i]>a[j])     //swaps minimum element to its right place

           {

               temp=a[i];

               a[i]=a[j];

               a[j]=temp;

           }

       }

   }

}

int main()

{

   srand(time(NULL));

   int arr[20],n=20,i;

   for(i=0;i<n;i++)

       arr[i]=rand() % 100 + 1;    //assigns random number to each array element

   cout<<"Before sorting\n";

   for(i=0;i<n;i++)

       cout<<arr[i]<<" ";   //prints array before calling sort func

   sort(arr,20);     //sort the passed array

   cout<<"\nAfter sorting\n";

   for(i=0;i<n;i++)

       cout<<arr[i]<<" ";  //prints array after sorting

   return 0;

}

OUTPUT :

Please find the attachment below.

Explanation:

The program above first assigns random number from 1 to 100 to each element of array using rand(). srand(time(NULL)) is used to generate new number every time otherwise same random number will be produced at a time. Then sorting method is called in which selection sort algorithm is used.

Selection sort algorithm finds the minimum element in each pass and place it into its right position. For example - 34,54,12,5 is passed

After Pass 1 - 5  54  12  34

After Pass 2 - 5  12  54  34

After Pass 3 -  5  12  34  54