Question

Q2. Consider the following C++ program that declares, allocates and fills in a1D array with random numbers between 0 and 100. The array is sent to a function that finds the indices of all items > 50. A new array is created and the indices are stored inside it. The size of the new arrays MUST BE the same as the number of items > 50. The function returns the new array which is then printed out by main.

Here is an example run:

Enter array size: 10 //your code MUST work for any other size > 0

Original array:

arr[0]= 81

arr[1]= 94

arr[2]= 90

arr[3]= 1

arr[4]= 77

arr[5]= 5

arr[6]= 49

arr[7]= 99

arr[8]= 1

arr[9]= 52

Indices of values > 50:

arr[0]= 0

arr[1]= 1

arr[2]= 2

arr[3]= 4

arr[4]= 7

arr[5]= 9

Press any key to continue . . .

Copy this code and declare and implement the returnIndexOfelementsGreaterThan(…) function.

This code does not compile as the function is not declared, so you need to declare it and implement it.

#include <iostream>

#include <ctime>

using namespace std;

void printArr(int* arr_in, int size);

int main()

{

     int size;

     cout << "Enter array size: ";

     cin >> size;

     if (size<0) {

           cout << "Size should be positive!\n";

           exit(0);

     }

     int* arr_in = new int[size];

     srand(time(0));

     for (int i = 0; i<size; i++) {

           arr_in[i] = rand() % 101;

     }

     cout << "Original array: \n";

     printArr(arr_in, size);

     int sizeOfnewArray = 0;

     int * indices = returnIndexOfelementsGreaterThan(arr_in, size, sizeOfnewArray);

     cout << "Indices of values > 50:\n";

     printArr(indices, sizeOfnewArray);

    

delete[] arr_in;

     delete[] indices;

     return 0;

}

void printArr(int* arr_in, int size){

     cout << "\n";

     for (int i = 0; i<size; i++)

           cout << "arr[" << i << "]= " << arr_in[i] << "\n";

     cout << "\n";

}

Answer 1

cpp code:

#include <iostream>
#include <ctime>

using namespace std;

//function declaration
void printArr(int * arr_in, int size);
int* returnIndexOfelementsGreaterThan(int *arr_in,int size,int &sizeOfnewArray);

int main()
{
int size;

//get the size of array
cout<<"Enter array size: ";
cin>>size;

//if negative, print error msg
if(size<0){
cout<<"Size should be positive!\n";
exit(0);
}

//allocate memory for array
int * arr_in=new int[size];
srand(time(0));

//assign random values
for(int i=0;i<size;i++){
arr_in[i]=rand()%101;
}

//call print function, print the original array
cout<<"Original array: \n";
printArr(arr_in,size);

//initialize new array to 0
int sizeOfnewArray=0;

//call function
int *indices =returnIndexOfelementsGreaterThan(arr_in,size,sizeOfnewArray);

cout<<"Indices of values > 50:\n";

//print array greater than 50
printArr(indices,sizeOfnewArray);

//deallocate memory
delete[] arr_in;
cout << endl;
return 0;
}

//print the array function
void printArr(int* arr_in, int size){
cout<<"\n";

//all elements in array
for(int i=0;i<size;i++)
cout<<"arr["<<i<<"]= "<<arr_in[i]<<"\n";

cout<<"\n";
}

//function that return array of index ,elements greater than 50
int* returnIndexOfelementsGreaterThan(int* arr_in, int size, int &sizeOfnewArray)
{
//new arr
int * arr=new int[size];

//go through all elements in array
for(int i=0;i<size;i++)
{
//if elements greater than 50
if(arr_in[i]>50)
{
//add indices to new array
arr[sizeOfnewArray]=i;
//increase the size
sizeOfnewArray++;
}

}
//return new array
return arr;
}

output:

C:\Users\NIROSHINI\Documents\CPPFiles\ElementGreaterlndex\bin\Debug\ElementGreaterlndex.exe Enter array size: 10 Original array: arr[@]= 70 arr[1]= 9 arr[2]= 52 arr[3]= 28 arr[4]= 37 arr[5]= 87 arr[6]= 47 arr[7]= 87 arr[8]= 18 arr[9]= 15 Indices of values > 50: arr[0]= 0 arr[1]= 2 arr[2]= 5 arr[3]= 7 execution time : 8.386 s Process returned 0 (0x0) Press any key to continue.

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