C++ Tutorial Index

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C++ Control Statements

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C++ Functions

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C++ Arrays

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C++ Strings

C++ Strings

C++ Inheritance

C++ Inheritance Single level Inheritance Multilevel Inheritance Multiple Inheritance Hierarchical Inheritance Hybrid Inheritance

C++ Polymorphism

C++ Polymorphism C++ Overloading C++ Overriding C++ Virtual Function

C++ Pointers

C++ Pointers C++ this pointer

C++ Exception Handling

C++ Exception Handling

C++ Constructors

C++ Constructors Default Constructor Parameterize Constructor Copy constructor Constructor Overloading Destructor

C++ File Handling

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Passing by the pointer in C++ Free vs delete() in C++ goto statement in C and C++ C++ program to read string using cin.getline() C++ String Concatenation Heap Sort in C++ Swap numbers in C++ Input Iterators in C++ Fibonacci Series in C++ C ++ Program: Alphabet Triangle and Number Triangle C++ Program: Matrix Multiplication C++ Program to Print Fibonacci Triangle Stack in C++ Maps in C++ Queue in C++ C++ Bitset C++ Algorithms Priority Queue in C++ C++ Multimap C++ Deque Function Pointer in C++ Sizeof() Operators in C++ C++ array of Pointers free() Vs delete in C Timsort Implementation Using C++ CPP Templates C++ Aggregation C++ Enumeration C++ Math Functions C++ Object Class C++ Queue Initialize Vector in C++ Vector in C++ C++ STL Components Function overloading in C++ C++ Maximum Index Problem C++ find missing in the second array C++ Program to find the product array puzzle C++ Program To Find Largest Subarray With 0 Sum C++ Program To Move All Zeros To The End Of The Array C++ Program to find the element that occurs once C++ Program to find the largest number formed from an array Constructor Vs Destructor C++ Namespaces C++ OOPs Concept C++ Static C++ Structs C++ Try-Catch C++ User Defined Exceptions C++ Virtual Destructor C++ vs C# Malloc() and new in C++ Palindrome Number Program in C++ Snake Code in C++ Splitting a string in C++ Structure Vs Class in C++ Virtual Function Vs Pure Virtual Function C++ Bidirectional Iterators C++ Forward Iterators C++ Iterators C++ Output Iterators C++ Range-based For Loop Converting string into integer in C++ LCM Program in C++ Type conversion in C++ Add two numbers using the function in C++ Advantage and disadvantage friend function C++ Armstrong Number Program in C++ ATM machine program in C++ using functions Binary to Decimal in C++ Bit Manipulation in C++ C++ Constructor C++ Dijkstra Algorithm Using the Priority Queue C++ int into String C++ Signal Handling Decimal to Binary in C++ Decimal to Hexadecimal in C++ Decimal to Octal in C++ Factorial Program in C++ Function in C++ Hexadecimal to Decimal in C++ Octal to Decimal in C++ Reverse a Number in C++ Structure Vs Class in C++ C++ Forward Iterators C++ Output Iterators C++ Prime number program Char Array to String in C++ Constructor Overloading in C++ Default arguments in C++ Different Ways to Compare Strings in C++ Dynamic Binding in C++ Program to convert infix to postfix expression in C++ SET Data Structure in C++ Upcasting and Downcasting in C++ Reverse an Array in C++ Fast Input and Output in C++ Delete Operator in C++ Copy elision in C++ C++ Date and Time C++ Bitwise XOR Operator Array of sets in C++ Binary Operator Overloading in C++ Binary Search in C++ Implementing the sets without C++ STL containers Scope Resolution Operator in C++ Smart pointers in C++ Types of polymorphism in C++ Exception Handling in C++ vs Java Const Keyword in C++ Type Casting in C++ Static keyword in C++ vs Java Inheritance in C++ vs Java How to concatenate two strings in C++ Programs to Print Pyramid Patterns in C++ swap() function in C++ Structure of C++ Program Stringstream in C++ and its applications rand() and srand() in C / C++ C++ Ternary Operator C++ Scope of Variables While Loop Examples in C++ Star pattern in C++ using For Loops For Loop Examples in C++ Do-While Loop Examples in C++ Top 5 IDEs for C++ That You Should Try Once Assertions in C/C++ C++ Convert Int to String Continue in C++ While loop Diamond Pattern in C++ using For Loop How to Reverse a String in C++ using Do-While Loop How to Reverse a String in C++ using For Loop How to Reverse a String in C++ using While Loop Infinite loop in C++ Loops in C++ Returning Multiple Values from a Function using Tuple and Pair in C++ wcscpy(), wcslen(), wcscmp() Functions in C++ Auto keyword in C++ C++ 11 vs C++ 14 vs C++ 17 C++ STL (Standard Template Library) Differences Between C Structures and C++ Structures Divide by Zero Exception in C++ Dynamic Constructor in C++ Dynamic Memory Allocation in C++ Find the Size of Array in C/C++ without using sizeof() function Floating Point Operations and Associativity in C, C++ and Java Hello World Program in C++ How to create a table in C++ How to Setup Environment for C++ Programming on Mac Implementation of a Falling Matrix in C++ Message Passing in C++ Pointer to Object in C++ Templates in C++ vs Generics in Java Ways to Copy a Vector in C++ What does Buffer Flush mean in C++ sort() function in C++ Structure Sorting (By Multiple Rules) in C++ Similarities between C++ and Java std::distance in C++

C++ array of Pointers

Array of Pointers:

In high-level programming languages like C++, the array's name is its pointer. The name of an array contains an address which is the address of an element. In C++, an array name is considered as the address of the first element. For instance, if we have an array of size 20, i.e., it can hold 20 values, then the value will contain the first element's address, i.e., array[0]. Thus, it can be said that name of the array is a pointer that holds the memory address of the first element present in the array.

In other words, an array of pointers is the array consisting of a variable of pointer types. This simply means that the pointer variable is addressing some other elements.

Syntax:     

int *pointer[N];

Here,

 *pointer = pointer array
 N = number of elements or size. 

Example: 

int *ptr[2];

Note: An array of the pointer can also be initialized by assigning the address of the variables like ptr[2] = &a.

There can be various ways of implementing an array of pointers. We may see its application in the arrays and similar data structures like linked-lists, strings, etc. The array of pointers comes in handy while implementing these programming practices efficiently.

To visualize how array of pointer work, let’s look at the below example:

 #include <iostream> 
 using namespace std; 
 int main() 
 { 
     int *pointer;   
     int array[10];
 cout << "Please enter the array elements :" <<endl; 
     for(int i=0;i<10;i++) 
     { 
         cin>>array[i]; 
     } 
     pointer = array;  
                       cout << "The value of *pointer :" <<*pointer<<endl; 
                       cout << "The value of *array :" <<*array<<endl; 
 Return 0;
 }  

Output:

C++ array of Pointers

Explanation:

In the above code, we implemented the array of pointers concerning an array that stores elements given by the user. As already discussed above, the array of pointers has the address of the first element of the array. We get the first element printed on the console. Therefore, we declared an integer pointer and integer type array, and we assigned the array to the pointer by equating pointer = array. It means that both have the same element, and the element is at the first index. The values for *pointer and *array will be the same since we have assigned them to be equal.

Let us now look at how the arrays of pointers are used to implement strings using the example code given below.

String application of array pointers:

 #include<bits/stdc++.h>
 using namespace std;
 const int Maximum = 4;
 int main ()
 {
 const char *pandavs[Maximum] = { "Nakul", "Bhim", "Yudhishthir",
                          "Sehdev" };
    for (int i = 0; i < Maximum; i++)
 {
       cout << "Addresses of pandavs: [" << i << "] = ";
       cout << (pandavs + i) << endl;
 }
    return 0;
 } 

Output:

C++ array of Pointers

Explanation:

In the above code, we have initialized the value of the array pointer to the maximum. Here, the maximum value can be anything, but to keep it simple and sober, we fixed the size to 4. We have used the const keyword to preserve the value of the maximum to 4. The const keyword is used so that the maximum value or, say, the array's size doesn't increase more than 4. The next step is to loop over the array to access all the values' addresses through the pointer array associated. The addresses of each value are then printed on the console using an array of pointers.

Using array of pointers to print container values:

 #include<bits/stdc++.h>
 using namespace std;
 const int Maximum = 4;
 int main () {
    int  container[Maximum] = {10, 100, 200, 400};
    int *pointer[Maximum];
    for (int i = 0; i < Maximum; i++)
  {
       pointer[i] = &container[i];
   }
    for (int i = 0; i < Maximum; i++) {
       cout << "Value of container at position: [" << i << "] = ";
       cout << *pointer[i] << endl;
  }
    return 0;
 } 

Output:

C++ array of Pointers

Explanation:

In the above code, we have used a similar approach as we used in the string example. The value of maximum is constant (cannot be changed) and is kept 4. The only difference in this example is that we have used the container address which holds the integers. The next step is to iterate over the elements and by doing that we now know that each element in ptr, now holds a pointer to an int value.

The output generated is the values at their respective indexes.

Let us now look at some of the applications of array of pointers.

Applications

  1. The array of pointers comes in handy while making embedded systems. A temperature measuring system may need to scale up different sensors so we can use an array of pointers to hold the memory address of each sensor so that it will be very easy to manipulate the sensor status.
  • An array of pointers allows us to numerically index a large set of variables.
  • We can separately make pointer variables that can point to different values or we can make one integer array of pointers to point all the values.



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