C++ Tutorial index

C++ Tutorial C++ History C++ installation C++ First Program C++ cin and cout C++ Data type C++ Variable C++ operator C++ Keywords C++ OOPS Concepts C++ Comments C++ Data Abstraction C++ Identifier C++ Memory Management C++ Storage Classes C++ Void Pointer C++ Array to function C++ Expressions C++ Features C++ Interfaces C++ Encapsulation

C++ Control Statements

C++ If C++ Nested if C++ If-else C++ If-else-if C++ Switch C++ Break C++ Continue C++ Goto C++ for loop C++ While loop C++ Do while loop

C++ functions

function in C++ C++ Call by Value C++ Call by Reference C++ Recursion function C++ inline function C++ Friend function C++ Friend functions function Pointer in C++ Sizeof() Operators in C++ C++ Math functions swap() function in C++ rand() and srand() in C / C++ wcscpy(), wcslen(), wcscmp() functions in C++ sort() function in C++ C++ vardiac() function System() function in C++ Fread function in C++ Programming Fscanf function in The C++ Gmtime function in C/C++ abs() function in C++ Sleep function in C++ Stoi function in C++ String erase() in C++ String Trim in C++ isprint() function in c++ is_trivial function in C++ div() function in C++ Set insert function in C++ rint(), rintf(), rintl() in C++ String append() function in C++ String push_back() in C++ String replace() in C++ Transform function in C++ exit() and _Exit() in C and C++ Std partition_point in C++ unique() in C++ ctime() function in C++ Gets() and Puts() in C++ Hypot(), hypotf() and hypotl() in C++ Log function in C++ Nearbyint() function in C++ setf() function in C++ Fill Function in C++ Map Find Function in C++ Malloc and Calloc in C++ Operator Function in C++ cin.get() in C++ seekp() Function in C++ eof() Function in C++ Emplace Back in C++ C++ macro function C_str in C++ Clock() in C/C++ round() function in C++ scalbn() function in C++ Stable Sort function in C++ Rotate in C++ Std:: Sort_heap in C++ Std::includes() in C++ STL std::memset() function in C++ Wcscmp() function in C++ Static Member function in C++ atof() function in C++ C++ Sin() function with Example cin.ignore() function in C++ Member function in C++ Pop_front Vector in C++ Vector resize() in C++ Malloc() and new in C++ std::distance in C++ C++ Date and Time fork() in C++ std::min in C++ isprint() in C++ rdbuf() in C++ fixed() Function in C++ setw() in C++ seekg() Function in C++ isdigit() Function in C++

C++ Function Miscellaneous

Precision of floating point numbers Using these functions floor(), ceil(), trunc(), round() and setprecision() in C++ function overloading in C++ Add two numbers using the function in C++ Advantage and disadvantage friend function C++ ATM machine program in C++ using functions Returning Multiple Values from a function using Tuple and Pair in C++ Find the Size of Array in C/C++ without using sizeof() function Pure Virtual function in C++ With Example Program Returning a function Pointer from a function in C/C++ Passing a Vector to a function in C++ functions in C++ With Types and Examples C++ Macro function Example Using Default Arguments with Virtual functions Virtual functions and Runtime Polymorphism Fesetround() and Fegetround() in C++ and their application Object as function Argument in C++ Private Member function in C++ Function Overriding in C++ C++ Program for Addition of Two Numbers Using functions function Object in C++ Elements of User Defined function in C++ Inline Functions in C++ Virtual Function in C++

C++ Arrays

Single dimension array Two dimension array

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

C++ File Handling C++ Writing to file C++ Reading file C++ Close file

C++ Programs

Structure of C++ Program Hello World Program in C++ C++ Program to Implement Shell Sort C++ Program to Implement Merge Sort C++ program to read string using cin.getline() C ++ Program: Alphabet Triangle and Number Triangle C++ Program: Matrix Multiplication C++ Program to Print Fibonacci Triangle 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 Palindrome Number Program in C++ LCM Program in C++ Armstrong Number Program in C++ Factorial Program in C++ C++ Prime number program Program to convert infix to postfix expression in C++ Programs to Print Pyramid Patterns in C++ Array program in C++ Pattern programs in C++ Leap Year Program in C++ C++ Program for FCFS Depth First Search Program to Traverse a Graph in C++ inheritance Program in C++ Program that produces different results in C and C++ Example Program in C++ for input and Output Calculator Program using Switch in C++ Program for COPY Constructor in C++ Bank Program in C++ Anagram Program in C++

C++ Operators

Unary Operators in C++ Delete Operator in C++ C++ Bitwise XOR Operator Binary Operator Overloading in C++ Scope Resolution Operator in C++ C++ Ternary Operator New Operator in C++ Overloading array index operator in C++ Operator overloading in C++ Operators that cannot be overloaded in C++ Default Assignment Operator and References in C++ Conversion Operator in C++ Unary Operator Overloading in C++ Benefits of Operator Overloading in C++ Assignment Operator Overloading in C++ New and Delete Operator in C++ Insertion Operator in C++ Increment Operator in C++ Bitwise Operator in C++

C++ Examples

C++ Programming Examples While Loop Examples in C++ for Loop Examples in C++ Do-While Loop Examples in C++ SDL library in C++ with Examples C++ tcp client server example C++ tcp server example TCP Client Server Example in C++ Example of Parameterized Constructor in C++ Example of User Defined Data Type in C++

C++ Differences

C Vs C++ free() vs delete() in C++ Constructor Vs Destructor Passing by Reference Vs. Passing by the pointer in C++ C++ vs C# Structure Vs Class in C++ Virtual function Vs Pure Virtual function Structure Vs Class in C++ Exception Handling in C++ vs Java Static keyword in C++ vs Java inheritance in C++ vs Java C++ 11 vs C++ 14 vs C++ 17 Templates in C++ vs Generics in Java Bitwise Operator vs Logical Operator Type difference of Character literals in C VS C++ Copy Constructor vs Assignment Operator in C++ Map vs unordered_map in C++ Differences between #define & const in C/C++ Differences Between C Structures and C++ Structures Difference between Two Sets in C++ Difference between Exit and Return Differences between Local and Global Variable Difference between OOP and POP in C++ Difference between exit() and _Exit() in C++ Difference between int main() and int main(void) in C/C++ Difference Between Overloading and Overriding in C++ std::set_symmetric_difference in C++ Difference between Private and Protected in C++ Difference Between Encapsulation and Abstraction in C++ Difference between Template and Macro in C++ Difference between Abstraction and Interface in C++ Differences Between C++ and Javascript Difference between POP and OOP in C++

How To

How to concatenate two strings in C++ 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 How to create a table in C++ How to Setup Environment for C++ Programming on Mac How to call a void function in C++ How to create a directory or folder in C/C++ How to create a library in C++ How to create a stack in C++ How to create the Processes with fork in C++ How to Handle Divide by Zero Exception in C++ How to Declare Unordered Sets in C++ How to Sort an Array in C++ How to run program in turbo c++ How to Use Getline in C++ How is Multiset Implemented in C++ How to Build a Program in C++ How to Declare a 2d Array Dynamically in C++ How to create a button in C++ How the value is passed in C++ How to calculate size of string in C++ How to convert binary string to int in C++ How to convert string to float in C++ How to remove space from string in C++ How to use pair in C++ How to use the string find() in C++ How to Remove an Element From an Array in C++ How to Take Space Separated input in C++ How to Copy in Turbo C++ How to Use Pow in C++ How to Use Set in C++ How to Create Singleton Class in C++ How to Allocate Memory Dynamically in C++ How to Close Turbo C++ in Windows 10 How to Use Modulus in C++

C++ Questions

What does Buffer Flush mean in C++ What is endl in C++ What is Unary Operator Overloading in C++ Which operators cannot be overloaded in C++ What is Static Member function in C++ What is This Pointer in C++ What is Upcasting in C++ What Kind of Exceptions Are Available in C++ What is Memory Allocation for Objects in C++ What is a Linked List in C++ is assignment operator inherited in C++ When should we write own Assignment operator in C++ What is an Object in C++ What is Copy Constructor in C++ What is a Static Member Function in C++

C++ Interview Questions

Advanced C++ interview Questions Oops Interview Questions in C++

Miscellaneous

External merge sort in C++ Remove duplicates from sorted array in C++ C++ References C++ Mutable keyword initialize Array of objects with parameterized constructors in C++ Storage Classes in C goto statement in C and C++ C++ String Concatenation Heap Sort in C++ Swap numbers in C++ input Iterators in C++ Fibonacci Series in C++ Stack in C++ Maps in C++ Queue in C++ C++ Bitset C++ Algorithms Priority Queue in C++ C++ Multimap C++ Deque C++ array of Pointers Timsort Implementation Using C++ CPP Templates C++ Aggregation C++ Enumeration C++ Object Class C++ Queue initialize Vector in C++ Vector in C++ C++ STL Components C++ Maximum index Problem C++ find missing in the second array C++ Namespaces C++ OOPs Concept C++ Static C++ Structs C++ Try-Catch C++ User Defined Exceptions C++ Virtual Destructor Snake Code in C++ Splitting a string in C++ C++ Bidirectional Iterators C++ forward Iterators C++ Iterators C++ Output Iterators C++ Range-based for Loop Converting string into integer in C++ Type conversion in C++ 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++ Hexadecimal to Decimal in C++ Octal to Decimal in C++ Reverse a Number in C++ C++ forward Iterators C++ Output Iterators 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++ SET Data Structure in C++ Upcasting and Downcasting in C++ Reverse an Array in C++ Fast input and Output in C++ Copy elision in C++ Array of sets in C++ Binary Search in C++ Implementing the sets without C++ STL containers Smart pointers in C++ Types of polymorphism in C++ Const Keyword in C++ Type Casting in C++ Stringstream in C++ and its applications C++ Scope of Variables Star pattern in C++ using for Loops 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 infinite loop in C++ Loops in C++ Auto keyword in C++ C++ STL (Standard Template Library) Divide by Zero Exception in C++ Dynamic Constructor in C++ Dynamic Memory Allocation in C++ Floating Point Operations and Associativity in C, C++ and Java Implementation of a Falling Matrix in C++ Message Passing in C++ Pointer to Object in C++ Ways to Copy a Vector in C++ Structure Sorting (By Multiple Rules) in C++ Similarities between C++ and Java C++ Tricks for Competitive Programming Desired Capabilities in Selenium Web Driver in C++ Socket Programming in C++ Template Specialization in C++ Classes and Objects in C++ Convex hull Algorithm in C++ DES in C++ Structured Binding in C++ Functors in C++ Lambda Expression in C++ Roadmap to C++ Programming Substring in C++ Virtual base class in C++ Bits stdc++.h in C++ Top 14 Best Free C++ IDE (Editor & Compiler) for Windows in 2022 Bitmasking in C++ Features of OOPS in C++ Hospital Management Project in C++ include Guards in C++ Iostream in C++ Method overriding in C++ Naming Convention in C++ Nullptr in C++ Object Slicing in C++ Principles of Object-Oriented Programming in C++ Processing strings using std string stream in C++ Random Number Generator in C++ Singleton Design Pattern in C++ Size_t Data Type in C++ Skyline Problem in C++ Web Development in C++ Data Hiding in C++ Hashing in C++ Object in C++ Sum of all Elements between k1’th and k2’th Smallest Elements Virtual class in C++ Vector Size in C++ Top best IDEs for C/C++ Developers in 2022 Tensorflow in C++ Sliding Window Technique in C++ Reverse String Word-Wise in C++ RTTI in C++ Pthreads or POSIX Threads in C++ Reserved Keywords in C++ 10 Best C and C++ Books for Beginners & Advanced Programmers Add two numbers represented by two arrays in C++ Array of Object in C++ Containership in C++ Counting Frequencies of Array Elements in C++ Decltype type Specifier in C++ Dynamic _Cast in C++ Features and Use of Pointers in C/C++ int Max and int Min in C/C++ is It Fine to Write Void Main Or Main in C/C++ Compile Time Polymorphism in C++ Division in C++ Factorial of a Number in C++ using while Loop Multiset in C++ 4 Pillars of OOPs Approach in C++ Backtracking Time Complexity in C++ C++ Global Variable C++ Pipe Tutorial Observer Design Pattern in C++ Private inheritance in C++ Pthread in C++ Parameters Pointers in C++ Abstract Factory Design Pattern in C++ Ascending order in C++ Call by Pointer in C++ Constexpr in C++ Deadlock in C++ Design Patterns in C++ Factory Method for Designing Pattern in C++ Name Mangling and extern in C++ Preventing Object Copy in C++ Quick Sort in C++ Single Handling in C++ Use of inheritance in C++ User-defined literals in C++ Vector methods in C++ Void * in C and C++ Zombie and Orphan Process in C++ List and Vector in C++ List iterators in C++ Merging Two Vectors in C++ Early Binding and Late Binding in C++ Factory Design Pattern in C++ Fisher-Yates shuffle algorithm in C++ for Auto in C++ Group anagrams in C++ Dynamic Casting in C++ 2D Vector initialization in C++ C++ GUI Visual Studio C++ IPC C++ Permutation Overloading Stream insertion in C++ Array sum in C++ STL C++ Define Macro C++ Design C++ Factory Pattern Convert String to Uppercase in C++ initializer list in C++ Iterator invalidation in C++ Lower bound in C++ Modulus of Two float numbers or double number Pass by value in C++ Stack size in C++ Unordered_map in C++ Binary String to int C++ Boost C++ Exception handling in constructor and destructor in C++ Explain class template in C++ Kadane Algorithm in C++ Map of Pairs in STL Pair in C++ Access Specifiers in C++ Add Two Numbers in C++ Using Class C++ Socket Programming Windows Cube root in C++ C++ Protected inheritance C++ Return Object Static Data Members in C++ Association in C++ Boost libraries in C++ Automatic Storage Class in C++ C++ Move Constructor Cast in C++ C++ 11 Lambda C++ Multithreading Bottom-up Approach in C++ C++ Static Class C++ Static Member C++ Static Variable C++ Template Class Implementation Kruskals Algorithm in C++ Kth Permutation Sequence in C++ Kth Smallest Element Using Priority Queue in C++ Min Heap in C++ Multilevel inheritance in C++ Playfair Cipher Algorithm in C++ Exception Handling in Java and C++ Sorting in C++ Time and Space Complexity for Loops in C++ Convert Vector To String in C++ Cascading in C++ Control Structure in C++ Passing Object as argument in C++ Vector Pair in C++ String Data Types in C++ Topological Sort in C++ C++ Move Semantics C++ Static Library Linking Call by Value and Call by Reference in C++ Data Structures algorithms and application in C++ Dereferencing a Pointer in C++ Linked List in C++ All Swing Components in C++ anonymous Object in C++ Cerr in C++ Control Flow Statement in C++ cstdlib in C++ Exception Objects in C++ Base Class and Derived Class in C++ Creating A Menu in C++ Escape Sequence in C++ Explicit in C++ int range in C++ Maximum Value in Vector in C++ NPTEL Programming in C++ Shared Pointer in C++ Static Member Function in C++ With Example The Diamond Pattern in C++ Const ptr C++ Const_Cast C++ Area Of Triangle in C++ Array input in C++ Cin String in C++ Coroutine in C++ Gui Design in C++ integer in C++ Advantages and Disadvantages of inheritance in C++ C++ IDE Linux C++ Mini Project With Source Code And Output C++ Variables Types Containers in C++ Dynamic Binding in C++ Explain Access Specifiers in C++ Iomanip in C++ Noexcept in C++ C++ Reference Initializer in C++ Constant Arguments in C++ Vector in C++ Stl Singleton Pattern in C++ Error Handling in C++ C++ Thread Id to Int C Str in C++ C++ Shared Ptr Scope Resolution Operator in C++ C++ Random Number Between 1 and 10 File Opening Mode in C++ New and Delete in C++ Big Integers in C++ Stack Unwinding in C++ C++ Syntax Link Map cbegin() and cend() function in C++ STL Hamming Code Implementation in C++ Files and Streams in C++ Private Destructor in C++ Semaphore in C++ Map Emplace_hint() function in C++ STL Complex Number Program in C++ Meta Classes in C++ C++ Delegates Custom Sort in C++ RAII in C++ Babylonian Square Root Algorithm in C++ File Input and output operation in C++ Sum of Digits of a Number in C++ C++ Type Traits Binary Search Tree Program in C++ Tree in C++ Built in Types in C++ Catch all Exceptions in C++ C++ Template Class Declaration and Definition C++ Generic Programming Introduction Fundamental Data Types in C++ API in C++ Menu Driven Program in C++ Exception Specification in C++ Bit Manipulation in C++ Dynamic Initialization Of Objects in C++ Returning Object from a Function in C++ Class and Structure in C++ Edmonds Karp Algorithm in C++ Flush in C++ Find Substring in C++ Input and Output Operators in C++ Final in C++ Lvalue and Rvalue in C++ C++ Singleton File Stream in C++ Has a Relationship in C++ Character Set in C++ Menu Driven Program in C++ Final Keyword in C++ Associative Containers in C++ Decltype in C++ Insert Function in C++ Metaclass in C++ Move Constructor in C++ Move Semantics in C++

Reverse an Array in C++

The many approaches to reverse an array in the C++ programming language will be discussed in this section. The term "reverse of an array" refers to changing the order of the elements in a given array. This approach turns the array's final element into the first, and the first element into the last. The procedure, however, continues until all of the array's letters or components have been entirely reversed.

For example, the array has items such as 'J', 'A', 'V', 'A', and when we reverse all of the elements of an array, we get 'J', 'A', 'V', 'A'. As a result, all of the characters in the array are reversed in this manner.

In the C++ programming language, there are several techniques to retrieve the reverse array.

  • Using for loop, reverse an array.
  • The reverse ( ) method may be used to reverse an array.
  • Using the user-defined function, reverse an array.
  • Using the pointers, reverse an array.
  • Using the Recursion function, reverse an array.

Using for loop to reverse an array

Let us loot at an example of a program in C++:

#include < iostream >  
#include < bits/stdc++.h >
#include < stdlib >
#include < stdio >
using namespace std ;  
int main ( )  
{  
    int arr [ 50 ] , num , temp , i , j ;  
    cout << " Please, enter the total no. you want to enter: " ;  
    cin >> num ;  
    // use for loop to enter the numbers   
    for ( i = 0 ; i < num ; i++ )  
    {  
        cout << " Enter the element " << i + 1 << ": " ;  
        cin >> arr [ i ] ;  
    }  
    for ( i = 0 , j = num - 1 ; i < num / 2 ; i++ , j-- )  
    {     
        temp = arr [ i ] ;  
        arr [ i ] = arr [ j ] ;  
        arr [ j ] = temp ;  
    }  
    cout << "\n Reverse all elements of the array: " << endl ;  
    // use for loop to print the reverse array  
    for ( i = 0 ; i < num ; i++ )  
    {  
        cout << arr [ i ] << " " ;  
    }  
    return 0 ;  
}

OUTPUT:

Please, enter the total no. you want to enter: 6
 Enter the element 1: 78
 Enter the element 2: 12
 Enter the element 3: 54
 Enter the element 4: 24
 Enter the element 5: 7
 Enter the element 6: 90


Reverse all elements of the array:
90 7 24 54 12 78
………………………………………………………………………
Process executed in 0.11 seconds
Press any key to continue.

Explanation:

In the above program in C++, we are using for loop to reverse an array of integer in which we are iterating till num and using a swap function using a temp variable to swap the numbers.

The reverse() method to reverse an array.

Let's look at an example of utilizing the reverse () function in C++ to output the reverse of an array:

#include < iostream >  
#include < bits/stdc++.h >
#include < stdio >
#include < stdlib >
#include < algorithm >  
using namespace std ;  
// declare disp ( ) function   
void disp ( int arr1 [ ] , int num )  
{  
    int i ;  
    // use for loop to iterate the characters  
    for ( i = 0 ; i < num ; i++ )  
    {  
        cout << arr1 [ i ] << " " ;  
    }  
}  
// define reverse ( ) function to reverse the array elements  
void reverse ( int arr1 [ ] , int num )  
{  
    reverse ( arr1 , arr1 + num ) ;   
}  
int main ( )  
{  
    // declare and initialize an array  
    int arr1 [ ] = { 34 , 78 , 21 , 90 , 5 , 2 } ;  
    int num = sizeof ( arr1 ) / sizeof ( arr1 [ 0 ] ) ;  
    // call reverse function and pass parameters  
    reverse ( arr1 , num ) ;  
    disp ( arr1 , num ) ; /* call disp ( ) function to print the revrse array. */  
    return 0 ;   
}

OUTPUT:

2 5 90 21 78 34
……………………..
Process executed in 0.11 seconds
Press any key to continue.

Explanation:

In the above example in C++, we are using a reverse function which takes an array of integer and a num as a parameter which performs the reverse function in C++.

The user-defined function to reverse an array

Let's look at an example of utilizing the user-defined in C++ to display the reverse of array members:

#include < iostream >  
#include < bits/stdc++.h >
#include < algorithm >
#include < stdio >
#include < stdlib >
using namespace std ;  
void ArrRev ( int [ ] , int ) ;  
int main ( )  
{  
    int arr [ 50 ] , num , i , j , temp ;  
    cout << " Number of elements to be entered: " << endl ;  
    cin >> num ;  
    cout << " Enter the array elements: " << endl ;  
    // use for loop to enter the elements  
    for ( i = 0 ; i < num ; i++ )  
    {  
        cin >> arr [ i ] ;  
    }  
    cout << " Elements are: \n" ;  
    // display entered elements in array  
    for ( i = 0 ; i < num ; i++ )  
    {  
        cout << arr [ i ] << " " ;  
    }  
    ArrRev ( arr , num ) ; // call function  
    cout << " \n The reverse of the given array is: \n" ;  
    // use for loop to print the reverse array elements  
    for ( i = 0 ; i < num ; i++ )  
    {  
        cout << arr [ i ] << " " ;  
    }  
    cout << endl ;  
    return 0 ;  
}  
void ArrRev ( int ar[], int a2)  
{  
    int i, j, temp;  
    j = a2 - 1;  
    for ( i = 0; i < j; i++, j--)  
    {  
        temp = ar[i];  
        ar[i] = ar[j];  
        ar[j] = temp;  
    }  
}

OUTPUT:

Number of elements to be entered:
7
 Enter the array elements:
45
32
89
21
78
34
65
Elements are:
45 32 89 21 78 34 65
The reverse of the given array is:
65 34 78 21 89 32 45
………………………………………………..
Proce3ss executed in 0.22 seconds
Press any key to continue.

Explanation:

In the above example of a program in C++, we used a user define function ArrRev which takes an array of type integer and the size of the array and also using for loop to display the elements of the array.

Using the pointers to reverse an array

Let's look at an example that shows how to reverse array members in C++ using pointers:

#include < iostream >  
#include < bits/stdc++ >
#include < stdlib >
#include < stdio >
using namespace std ;  
int main ( )  
{  
    // declare the size of array  
    int arr [ 50 ] , arr2 [ 50 ] ;  
    int * ptr , i , num ;  
    cout <<" No. of array elements to be entered: "<< endl ;  
    cin >> num ;     
      
    cout <<" Enter the elements: " ;  
    // use for loop to insert the array elements  
    for ( i = 0 ; i  <  num ; i++ )  
    {  
        cin >> arr [ i ] ;  
    }  
    ptr = & arr [ 0 ] ;  
    cout <<" Entered elements of the array are: \n" <<endl ;  
    for ( i = 0 ; i < num ; i++ )  
    {  
        cout << "\t" << * ptr ;  
        ptr++ ;  
    }  
    ptr-- ; // decrement ptr  
    for ( i = 0 ; i < num ; i++ )  
    {  
        arr2 [ i ] = * ptr ;  
        ptr-- ;  
    }  
    ptr = & arr2 [ 0 ] ;  
    for ( i = 0 ; i < num ; i++ )  
    {  
        arr [ i ] = * ptr ;  
        ptr++ ; // increment ptr  
    }  
    ptr = & arr [ 0 ] ; // ptr hold the base address of arr [ 0 ]  
    cout <<" \n The reversed array elements are: \n " << endl ;  
      
    // print the array elements using ptr  
    for ( i = 0 ; i < num ; i++ )  
    {  
        cout <<" \t " << * ptr << endl ;  
        ptr++ ;  
    }  
    return 0 ;  
}  

OUTPUT

No. of array elements to be entered:
6
 Enter the elements: 45
32
89
63
4
6
Entered elements of the array are: 
45      32      89      63      4       6
The reversed array elements are: 
         6
         4
         63
         89
         32
         45
…………………………………………………
Process executed in 0.11 seconds
Press any key to continue.

Explanation:

In the above example of a program in C++, we have used pointer ptr which stores the address of array at index zero and using for loop it stores all the address of the elements present in the array and incrementing ptr in each iteration.

Using the Recursion function to reverse an array

Let's use the recursion function in C++ to develop a program that reverses the array items:

#include < iostream >  
#include < bits/stdc++.h >
#include < stdio >
#include < stdlib >
#include < algorithm > 
using namespace std ;  
// initialize array  
int arr [ ] = { 20 , 34 , 5 , 8 , 1 , 78 } ;  
// size of the array  
int size = sizeof ( arr ) / sizeof ( arr [ 0 ] ) ;  
void reverseArr ( int arr [ ] , int num )  
{  
    // check the size of array  
    if ( num == size )  
        return ;  
    // extract array elements  
    int elem = arr [ num ] ;  
    // recursively calls the next element of the array  
    reverseArr ( arr , num + 1 ) ;  
    // assigning elements  
    arr [ size - num - 1 ] = elem ;  
}  
int main ( )  
{  
    int i ;  
    // call recursive function (start from first elements  
    cout << " Original elements of the arrays " << endl ;  
    for ( int i = 0 ; i < size ; i++ )  
    {  
        cout << arr [ i ] << " " ;  
    }  
    reverseArr ( arr , 0 ) ;  
    cout << " \n Reverse elements of the array are: " << endl ;  
    // display the array elements  
    for ( int i = 0 ; i < size ; i++ )  
    {  
        cout << arr [ i ] << " " ;  
    }  
    return 0 ;  
}  

OUTPUT:

Original elements of the arrays
20 34 5 8 1 78
Reverse elements of the array are:
78 1 8 5 34 20
………………………………………………
Process executed in 0.11 seconds
Press any key to continue.

Explanation:

In the above example of a program in C++, we have used the concept of recursion to reverse the elements of an array. First we are printing the original array by applying for loop and displaying it, then recursively passing arr and 0 to the function reverseArr.

Let us look at  another example to better understand:

// Recursive C++ program to reverse an array
#include < bits/stdc++.h >
#include < iostream >
#include < stdlib >
#include < stdio >
using namespace std ; 
/* Function to reverse arr [ ] from start to end*/
void rvereseArray(int arr [ ] , int start , int end )
{
	if ( start >= end )
	return ; 
	int temp = arr [ start ] ;
	arr [ start ] = arr [ end ] ;
	arr [ end ] = temp ; 
	// Recursive Function calling
	rvereseArray ( arr , start + 1 , end - 1 ) ;
}	
/* Utility function to print an array */
void printArray(int arr[], int size)
{
for ( int i = 0 ; i < size ; i++ )
cout << arr [ i ] << " " ; 
cout << endl ;
}
/* Driver function to test above functions */
int main ( )
{
	int arr [ ] = { 1 , 2 , 3 , 4 , 5 , 6 } ; 
	// To print original array
	printArray ( arr , 6 ) ; 
	// Function calling
	rvereseArray ( arr , 0 , 5 ) ; 
	cout << "Reversed array is" << endl ; 
	// To print the Reversed array
	printArray ( arr , 6 ) ; 
	return 0 ;
}

OUTPUT:

1 2 3 4 5 6 
Reversed array is 
6 5 4 3 2 1

Explanation

In the above example of a program in C++, we demonstrated another way of recursive method to find the reverse of an array. We are creating a temp variable which does our swapping then we recursively calling start plus one and end minus one which moves both of the variable iterator from left to right and visa versa.

Miscellaneous Program

Using Stack Data Structure:

#include < iostream >
#Include < bits/stdc++.h >
#include < stdlib >
#include < stdio >
#include < stack >
using namespace std ; 
// Utility function to print contents of an array
void print ( int arr [ ] , int n )
{
	for ( int i = 0 ; i < n ; i++ ) {
		cout << arr [ i ] << " " ;
	}
}
// Utility function to reverse elements of an array
void reverse ( int arr [ ] , int n )
{
	// create an empty stack of integers
	stack < int > stack ; 
	// push each array element into a stack
	for ( int i = 0 ; i < n ; i++ ) {
		stack . push ( arr [ i ] ) ;
	}
	// start from index 0
	int index = 0 ; 
	// pop values from the stack until it becomes empty
	while ( ! stack . empty ( ) )
	{
		// assign each popped item back to the original array
		arr [ index++ ] = stack.top ( ) ;
		stack . pop ( ) ;
	}
}
int main ( )
{
	int arr [ ] = { 1, 2, 3, 4, 5 } ;
	int n = sizeof ( arr ) / sizeof ( arr [ 0 ] ) ; 
	reverse ( arr , n ) ; 
	print ( arr , n ) ; 
	return 0 ;
}

OUTPUT:

5 4 3 2 1
………………..
Process executed in 0.11 seconds
Press any key to continue.

Explanation

In the above example of a program in C++, we have used stack data structure. We have created a stack and using the push function in stack STL we pushed our array elements in stack one by one then we bring top to the top element in our stack and popping it out one by one which gives our reversed array.