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C++ Control Statements

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C++ Exception Handling

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Miscellaneous

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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++

Reverse a Number in C++

In this tutorial, you'll learn how to utilize a C++ program to reverse a number entered by a user at runtime. Because there are various ways to write a C++ program to reverse a number, we've utilized a well-known approach to do the task, as seen below:

  • Reverse a number using a while loop
  • Using a for loop
  • Using function
  • Using an array

Reverse a number using while loop

To reverse a number in C++ programming, you must first request that the user supply a number. Now get the inverse of that number and print it on the output as demonstrated in the following program:

The task is to develop a C++ program that reverses a number. Here's what it says:

#include < iostream >
#include < bits/stdc++.h >
#include < stdlib >
using namespace std ;
int main ( )
{
    int num , rem , rev = 0 ; 
    cout << "enter the Number: " ;
    cin >> num ; 
    while ( num ! = 0 )
    {
        rem = num % 10 ;
        rev = rem + ( rev * 10 ) ;
        num = num / 10 ;
    }
    cout <<"\nReverse = " << rev ;
    cout << endl ;
    return 0 ;
}

OUTPUT:

Enter the Number: 123
321
………………………………….
Process executed in 1.112 seconds
Press any key to continue.

Explanation:

rev=0, initial value When a user types in the number 123, it is saved in the num field. Now that the condition num!=0 (of the while loop) or 123!=0 is true, program flow enters the loop and all three lines are executed. That is, rem is initialized to num percent 10 or 123 percent 10 or 3. Then rev is initialized to rem + (rev*10) or 3 + (0*10) or 3. So rev=3 num/10, 123/10, or 12 is eventually initialized to num. So num=12 after performing all three while loop statements, the condition is assessed one again.

Using a Loop

Instead of utilizing the while loop, this program uses the for loop. The rest of the software is identical to the previous one:

#include < iostream >
#include < bits/stdc++.h >
#include < stdlib >
using namespace std ;
int main ( )
{
    int number , remainder , rev ;
    cout <<"enter the Number: " ;
    cin >> number ;
    for ( rev = 0 ; number ! = 0 ; number = number / 10 )
    {
        remainder = num % 10 ;
        rev = remainder + ( rev * 10 ) ;
    }
    cout <<"\nReverse = "<<  rev ;
    cout << endl ;
    return 0 ;
}

OUTPUT:

Enter the Number: 23056
65032
…………………………………….
Process executed in 0.22 seconds
Press any key to continue.

Explanation:

Here in the above code we are using the for loop in the line number 10 which is taking rev integer and will iterate till n is not equal to zero.

Without Using Loops

To reverse a number, this program does not require any form of loop, neither for nor while. First, have a look at the software; the explanation will follow:

#include < iostream >
#include < bits/stdc++.h >
#include < stdlib >
using namespace std ;
int main ( )
{
    int num , rem , rev = 0 ;
    cout <<"enter the Number: " ;
    cin >> num ;
    CODeReVeRSe:
        rem = num % 10 ;
        rev = ( rev * 10 ) + rem ;
        num = num / 10 ;
        if ( num ! = 0 )
            goto CODeReVeRSe ;
    cout <<"\nReverse = "<< rev ;
    cout << endl ;
    return 0 ;
}

OUTPUT:

Enter the Number: 23056
65032
……………………………………
Process executed in 0.133 seconds
Press any key to continue.

Explanation:

CODEREVERSE is a label in which all three statements for reversing a number are written. We used if for the condition ( to check ) after running all three statements, like we did in the while loop. If the condition evaluates to true, the program flow returns to the label using the goto keyword followed by the label name.

Using Function

To reverse an integer, this application employs the rev ( ) user-defined function. It accepts a number as an input and returns the opposite. Example:

#include < iostream >
#include < bits/stdc++.h >
#include < stdlib >
using namespace std ;
int rev ( int ) ;
int main ( )
{
    int number , i ; 
    cout <<"enter the Number: " ;
    cin >> number ;
    i = rev ( number ) ;
    cout <<"\nReverse = "<< i ;
    cout << endl ;
    return 0 ; 
}
int rev ( int x )
{
    int remainder , res = 0 ;
    while ( x != 0 ) 
    {
        remainder = x % 10 ;
        res = ( res * 10 ) + remainder ;
        x = x / 10 ;
    }
    return res ;
}

OUTPUT:

Enter the Number: 23056
65032
……………………………………
Process executed in 0.13 seconds
Press any key to continue.

Explanation:

In the above program we are making a function called rev which is taking integer x as a parameter and inside that function we are using while loop for our iterations till x integer is not equal to zero.



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