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  1. // Torrez, Elaine                         CS1A                          Chapter 9, P. 537, #1
  2.  
  3. /********************************************************************************************
  4.  *
  5.  * ALLOCATE INTEGER ARRAY
  6.  *
  7.  * ------------------------------------------------------------------------------------------
  8.  * This program demonstrates a function that dynamically allocates an array of integers.
  9.  * The program asks the user how many integers to store, allocates the array, allows the
  10.  * user to enter the values, and then displays the integers back to the user.
  11.  *
  12.  * ------------------------------------------------------------------------------------------
  13.  * INPUT
  14.  *
  15.  *      numElems    : Number of integers to store in the array
  16.  *      values      : Each integer value entered by the user
  17.  *
  18.  * OUTPUT
  19.  *
  20.  *      values      : The list of integers stored in the dynamically allocated array
  21.  *
  22.  ********************************************************************************************/
  23.  
  24. #include <iostream>
  25. using namespace std;
  26.  
  27. // FUNCTION PROTOTYPE
  28. int *allocateArray(int size);     // Dynamically allocates an int array and returns a pointer
  29.  
  30. int main ()
  31. {
  32.     int  numElems;                // Number of elements to allocate
  33.     int *numbers = nullptr;       // Pointer to the dynamically allocated array
  34.  
  35.     // INPUT: Ask user how many integers the array should hold
  36.     cout << "How many integers would you like to store? ";
  37.     cin  >> numElems;
  38.  
  39.     // INPUT VALIDATION: Number of elements must be greater than 0
  40.     while (numElems <= 0)
  41.     {
  42.         cout << "Error: Number of elements must be greater than 0. Try again: ";
  43.         cin  >> numElems;
  44.     }
  45.  
  46.     // Call function to allocate the array
  47.     numbers = allocateArray(numElems);
  48.  
  49.     // INPUT: Fill the array with user-entered integers
  50.     cout << "\nEnter " << numElems << " integer values:\n";
  51.     for (int index = 0; index < numElems; index++)
  52.     {
  53.         cout << "Value #" << (index + 1) << ": ";
  54.         cin  >> *(numbers + index);       // Store value using pointer notation
  55.     }
  56.  
  57.     // OUTPUT: Display the integers stored in the array
  58.     cout << "\nYou entered:\n";
  59.     for (int index = 0; index < numElems; index++)
  60.     {
  61.         cout << "Element [" << index << "] = " << *(numbers + index) << endl;
  62.     }
  63.  
  64.     // Free dynamically allocated memory
  65.     delete [] numbers;
  66.     numbers = nullptr;
  67.  
  68.     return 0;
  69. }
  70.  
  71. //*******************************************************************************
  72. // allocateArray
  73. //------------------------------------------------------------------------------
  74. // This function accepts an integer argument indicating the number of elements
  75. // to allocate. It dynamically allocates an array of integers of that size and
  76. // returns a pointer to the first element of the array.
  77. //*******************************************************************************
  78. int *allocateArray(int size)
  79. {
  80.     int *ptr = nullptr;           // Pointer to the new array
  81.  
  82.     // Dynamically allocate the array
  83.     ptr = new int[size];
  84.  
  85.     return ptr;                   // Return pointer to the allocated array
  86. }
  87.  
Success #stdin #stdout 0.01s 5284KB
comments (?)
stdin
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5
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50
stdout
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How many integers would you like to store? 
Enter 5 integer values:
Value #1: Value #2: Value #3: Value #4: Value #5: 
You entered:
Element [0] = 10
Element [1] = 20
Element [2] = 30
Element [3] = 40
Element [4] = 50
https://ideone.com/xCWqto
language:
C++ (gcc 8.3)
created:
5 hours ago
visibility:
public

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