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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

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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

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C++ Exception Handling

C++ Exception Handling

C++ Constructors

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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++

C++ Range-based For Loop

In C++ language, the range-based for loop was added, which is far superior than the ordinary For loop. The implementation of a range-based for loop doesn't really need much code. It's a sequential generator that iterates each container element across a set of values (from beginning to end). This for loop is specifically used with collections such as arrays and vectors.

Syntax:

for (range_of_declaration : range_of_expression ) {
	// program code
}  
  • Range_of_declaration: It's used to define a variable with the same type as the accumulated items indicated by the range expression or a value to that type.
  • Range_of_expression: It defines a range expression that represents the appropriate sequence of items.
  • Program code: It specifies the content of the range-based for loop, which comprises one or even more lines to be repeated until the range-expression is finished.

We may use the auto keyword to automatically identify the data type of the range expression if we are not familiar with the data type of the contained items.

C++ Range-based For Loop

Fig. Ranged for Loop working

Range based For Loop Using Array:

This method is explained below using an example.

Example:

#include <iostream>
using namespace std;


int main() {


    // initializing an array  
    int numArrays[] = {10, 20, 30, 40, 50};


    // using ranged for loop to print the array of given elements  
    for (int x : numArrays) {
        cout << x << " ";
    }
  
    return 0;
}

Output:

10 20 30 40 50

Explanation:

We declared and initialised an int array namely numArrays in this example. To print the items in numArrays, we utilised the ranged for loop.

The first iteration accepts the value of an array's first element, which is 10, the second iteration uses the input of 20 and prints it, and so on.

The ranging for loop generates a sequence the array from start to finish automatically. The loop's number of iterations does not need to be specified.

Range based For Loop Using Vector:

This method is explained below using an example.

Example:

#include <iostream>
#include <vector>
using namespace std;


int main() {


    // declaring and initializing vector  
    vector<int> num_vect = {10, 20, 30, 40, 50};


    // printing the vector elements  
    for (int x : num_vect) {
        cout << x << " ";
    }
  
    return 0;
}

Output:

10 20 30 40 50

Explanation:

We declared and initialised a vector<int> array namely num_vect in this example. To print the items in num_vect, we utilised the ranged for loop.

The first iteration accepts the value represented by int x of an array's first element, which is 10, the second iteration uses the input of 20 and prints it, and so on.

Declaring a Collection inside the For Loop:

This method is explained below using an example.

Example:

#include <iostream>


using namespace std;


int main() {


    // defining the collection inside the loop itself
    for (int x : {10, 20, 30, 40, 50}) {
        cout << x << " ";
    }


    return 0;
}

Output:

10 20 30 40 50

Explanation:

The collection has been defined within the loop itself, i.e.

Ranged_Expression = {1, 2, 3, 4, 5}

This is also a legal technique to use the rangedg for loop, and it functions similarly to using a real array or vector.

Best Practices for C++ Ranged For Loops:

In each iteration of the for loop in the examples above, we declared a variable to hold every element of the collection.

int nums[3] = {10, 20, 30};


// copying the elements of nums to vars
for (int vars : nums) {
    // programming code
}

But it's preferable to write the range based for loop like follows:


// accessing the memory location of elements of nums
for (int &vars : nums) {
    // programming code
}

We should notice how & is used before var.

int vars: nums - In each iteration, replicates every element of nums here to vars variable. This is detrimental to computer memory.

int &vars: nums - Doesn't really replicate all of nums' elements to vars. Instead, nums' elements are accessed straight from nums. This is more practical.

The reference operator is represented by the & symbol and the C++ pointers will teach us more about it.

C++ Range-based For Loop

Fig. Address pointer working in ranged for Loop

Note: It is preferable using the const keyword in ranged declaration if we are not changing the array/vector/collection inside the loop.

Advantages of using Range-based for loop:

  • It's simple to use, and the syntax is straightforward.
  • The number of components in a container does not need to be calculated in a range-based for loop.
  • It detects the containers' beginning and ending components.
  • We can simply change the container's size and components.
  • It does not duplicate the components in any way.
  • It's a lot quicker than the standard for loop.
  • The auto keyword is commonly used to determine the data type of container components.

Disadvantages of using Range-based for loop:

  • It is unable to traverse a section of a list.
  • It can't be utilised to go backwards in time.
  • It is not suitable for usage in pointers.
  • It does not include a current element index.



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