Question

Write a C++ program to scale and average the values in a two-dimensional array. Write the following functions:

          void randomize2DArray(int arr[ROW_SIZE][COL_SIZE]) – places random values between 1 and 100 in a two-dimensional array .

          void scale2DArray(int arr[ROW_SIZE][COL_SIZE], double scale) – multiplies every value in the two-dimensional array by scale.

          double average2DArray(int arr[ROW_SIZE][COL_SIZE]) – calculates the average value over all elements in the two-dimensional array.

Randomize and print the values in the two-dimensional array of size 7 x 10. Then determine and print the average value. Then prompt for and get a scale value in the range 0.5 and 1.5 from the user. Scale and print the array. Create global constants for the array row and column sizes.

Answer 1

code:-

#include <iostream>
#include <ctime>
#include <cstdlib>
#define ROW_SIZE 7
#define COL_SIZE 10
using namespace std;
int arr[ROW_SIZE][COL_SIZE];//a global array

void randomize2DArray(int arr[ROW_SIZE][COL_SIZE])
{
    srand ((unsigned)time(NULL));

    int i,j;// loop counters
    for(i=0; i<ROW_SIZE; i++)
    {
        for(j=0; j<COL_SIZE; j++)
            arr[i][j] = rand()%100 + 1;
    }
}

void scale2DArray(int arr[ROW_SIZE][COL_SIZE],double scale)
{
    int i,j;
    for(i=0; i<ROW_SIZE; i++)
    {
        for(j=0; j<COL_SIZE; j++)
            arr[i][j] = scale*arr[i][j];
    }
}

double average2DArray(int arr[ROW_SIZE][COL_SIZE])
{
    double avg;
    double total = 0.0;
    int i,j;
    for(i=0; i<ROW_SIZE; i++)
    {
        for(j=0; j<COL_SIZE; j++)
            total = total + arr[i][j] ;
    }
    avg = total / (double)(ROW_SIZE * COL_SIZE);
    return avg;

}

int main()
{

    randomize2DArray(arr);
    int i,j;
    cout<<"\nArray is"<<endl;
    for(i=0; i<ROW_SIZE; i++)
    {
        for(j=0; j<COL_SIZE; j++)
            {
                cout<<arr[i][j]<<" ";
            }
            cout<<endl;
    }
    double scale;
    cout<<"\nEnter the scaling value between 0.5 and 1.5 ";
    cin>>scale;
    while(scale>1.5 || scale<0.5)
    {
        cout<<"\nyou have entered out of range scaling factor \nplease enter the correct scaling factor:";
        cin>>scale;
    }
    scale2DArray(arr,scale);
    cout<<"\nScaled array is"<<endl;
    for(i=0; i<ROW_SIZE; i++)
    {
        for(j=0; j<COL_SIZE; j++)
            {
                cout<<arr[i][j]<<" ";
            }
            cout<<endl;
    }
    double avg = average2DArray(arr);
    cout<<"\nThe average of all the values of 2D array is "<<avg<<endl;

    return 0;
}

output:-