Question

I need you to do both of the programs. Please specify which program is which!

Array Allocator:

Write a function that dynamically allocates an array of integers. The function should accept an integer argument indicating the number of elements to allocate. The function should return a pointer to the array. Call the function in a complete program.

Reverse Array:

Write a function that accepts an int array and the array’s size as arguments. The function should create a copy of the array, except that the element values should be reversed in the copy. The function should return a pointer to the new array. Demonstrate the function in a complete program.

Answer 1

PROGRAM 1ST:

Array Allocator:

#include<iostream>
using namespace std;

//numberInput is itself a argument of function allocating and 
//number is argument of numberInput
int numberInput(int number);

//allocating with argument numberInput
int* allocating(int numberInput);

//main function
int main()
{
    //initialize number is equal to 0
    int number=0;

    //array
    int *array;
    number = numberInput(number);
    array=allocating(number);
    //priting dynamically allocating array values at last
    for(int i=0;i<number;i++)
    {
        cout<<array[i]<<endl;
    }
}
   //number is the array size
    int numberInput(int number)
    {
        cout<<"enter the array size \n";
       //inputting number value from user 
        cin>>number;
        return number;
    }
    int* allocating(int numberInput)
    {
       //dynamic allocate to a new array
        int *array = new int(numberInput);
       
        for(int i=0;i<numberInput;i++)
        {
           //Enter number from user
            cout<<"Enter number"<<i+1<<endl;
            cin>>array[i];
        }
      //returning save values in new array
        return array;
    }

The output of the program is as:

Reverse Array:

#include<iostream>
using namespace std;

//reverseArray function
int* reverseArray(int *, int);

int main()
{
    //declaring size of array using SIZE 
    const int SIZE = 10;
    //a simple example to show a demonstrate view of array size 10
    int array[SIZE] = {12,2,3,4,5,6,7,8,9,33};

    // It will print the elements of array that is already declared
    cout<< "Starting array: \n";
    for(int i = 0; i<SIZE; i++)
        cout<< *(array + i) << " ";

    // taking arumments array, and SIZE
    int *revArray = reverseArray(array, SIZE);

    // Reversing array using revARR
    cout<< "\n\nReversed array: \n";
    for(int i = 0; i<SIZE; i++)
        cout<<*(revArray + i) <<" ";
    cout<< endl;
    
    // Deleting memory allocation of revArray
    delete [] revArray;
    return 0;
}

//reverseArray function with arguments array and SIZE
int* reverseArray(int *array, int SIZE){
// allocating dynamically a new array
int *ptr = new int[SIZE];

//saving the value of original array in reverse order to new one
for(int i=0; i<SIZE; i++){
    *(ptr + SIZE - 1 - i) = *(array + i);
}

//returning the pointer to new one
return ptr;
}

The Output of the program is as:

C Program of ReverseArray without function:

#include<stdio.h>
#include<stdlib.h>
#include<string.h>
#include<math.h>
/* malloc is used in a dynamic array to allocate memory to array/structure
  and free is used to clear the memory or delete the allocated memory
  */
int main()
{
    int n, sum=0; //n is for size of array
    printf("Enter the size of array: \n");
    scanf("%d", &n);  //inputting array size
    printf("Enter elements of array: \n");
    int *value;   //*value is array
    value = (int*) malloc(n*sizeof(int));  // where int* is typecasting
    for(int i=0; i<n; i++)
        scanf("%d",&value[i]);
    
   //for loop is used to print reverse array elements 
    for(int i=n-1; i>=0; i--)
        printf("%d ",*(value+i));  //Printing array elements in reverse order
   //clearing/deleting the memory
    free(value);   
}

The output of the program is as: