Question

in C++

Given two integer arrays sorted in the ascending order, code the function SortArrays to merge them into one array in the descending order. You need to make sure if the values in the arrays are changed, it will still work. (25 points)

#include <iostream>

using namespace std;

void SortArrays (int a[], int b[], int c[], int size);

void printArray(int m[], int length);

const int NUM = 5;

int main()

{

int arrA[NUM] = {-2, 31, 43, 55, 67};

int arrB[NUM] = {-4, 9, 11, 17, 19};

int result[2*NUM];

SortArrays(arrA, arrB, result, NUM);

printArray(result, 2*NUM);

return 0;

}

void SortArrays (int a[], int b[], int c[], int size)

{

}

void printArray(int m[], int length)

{

for(int i = 0; i < length; i++)

cout<< m[i]<<" ";

cout<<endl;

}

Answer 1

The C++ code along with the comments is given below.

#include <iostream>
using namespace std;

void SortArrays (int a[], int b[], int c[], int size);
void printArray(int m[], int length);

const int NUM = 5;

int main()
{
    int arrA[NUM] = {-2, 31, 43, 55, 67};
    int arrB[NUM] = {-4, 9, 11, 17, 19};
    int result[2*NUM];
    SortArrays(arrA, arrB, result, NUM);
    printArray(result, 2*NUM);
    return 0;
}

void SortArrays (int a[], int b[], int c[], int size)
{   int i,j,temp;

    //copy array a into array c
    for(i=0, j=0; i<size; i++, j++)
    {   c[i]=a[j];
    }
  
    //copy array b to the end of array c
    for(i=size, j=0; i<2*size; i++, j++)
    {   c[i]=b[j];
    }
  
    //sort the array c in descending order
    for(i=0; i<2*size; i++)
    {   for(j=i+1; j<2*size; j++)
        {   if(c[j]>c[i])   //if c[j]> c[i], then swap the values to make it in descending order
            {   temp=c[j]; //store c[j] to a variable
                c[j]=c[i]; //update c[j] with c[i]
                c[i]=temp; //update c[i] with value in the temp, now the values are swapped
            }
        }
    }
}

void printArray(int m[], int length)
{
    for(int i = 0; i < length; i++)
        cout<< m[i]<<" ";
    cout<<endl;
}

The screenshot of the function snippet is given below.

The output of the code is given below.

Explanation

• Two sorted arrays a and b are given. The aim is to create an array which merges the two sorted arrays in descending order. Let the resultant array be called c.
• Copy the contents of the array a to the array c. This is done by using a for loop to traverse each element of the array and stores them into the array c. Traversal of both arrays starts from the position one or the zeroth index.
• Append the contents of the array b to the array c. This is also done by using a for loop. But, the array c already has some contents in it. So, the starting position of the array c will be the index 'size' or (size+1)'th position.
• Now, the array c contains the contents of both the arrays a and b.
• Sort the array c in descending using any sorting method. Here, bubble sort is used.
• Each element is compared with the other elements and if an element is in wrong position, it will be swapped.
• In C++, there is no inbuilt method to swap two values. So, with the help of an extra variable, the two values will be swapped.
• The resultant array will be displayed in the output console.

Hope this helps. Doubts, if any, can be asked in the comment section.