C++ Tutorial Index

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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

C++ Call by Value C++ Call by Reference C++ Recursion Function C++ Inline function C++ Friend function

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

Miscellaneous

C Vs C++ 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 std::min in C++ External merge sort in C++ Remove duplicates from sorted array in C++ Precision of floating point numbers Using these functions floor(), ceil(), trunc(), round() and setprecision() in C++ C++ References C++ Friend Functions C++ Mutable keyword Unary Operators in C++ Initialize Array of objects with parameterized constructors in C++ Differences between #define & const in C/C++ C++ Program to Implement Shell Sort C++ Program to Implement Merge Sort Storage Classes in C Vector resize() in C++ Passing by Reference Vs. 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++

C++ Convert Int to String

In fact, the conversion of numbers to strings or vice versa represents a significant paradigm change. We often need to convert a number to a string or a string to a number in general, or more especially in competitive programming. But we can't do so fluently because we have inadequate knowledge of some crucial skills. In this article, a few approaches to doing this work are discussed.

Number to String Conversion in C++:

The three main ways to change a number into a string are as follows:

  • By using string Stream 
  • By using to_string()
  • By using boost lexical cast

First approach: String Streams:

In this method, a stream object is declared that first inserts a number as a stream into an object before using "str()" to carry out the internal conversion of a number to a string.

C++ Program:

#include<iostream> //header files
#include <sstream> 
#include <string>


using namespace std;
int main()
{
	//initializing an integer
	int value = 2001;


	ostringstream strng1;


	strng1 << value;


	// changing number into string
	string s1 = strng1.str();


	//printing the string
	cout << " The freshly created number string is: ";
	cout << s1 << endl;


	return 0;
}

Output:

The freshly created number string is: 2001
Time Complexity:  O(n)
Space Complexity:  O(n)

Second approach: to_string():

The to_string() method takes a number, which can be of any data type, and returns it as the specified string.

C++ Program:

#include <iostream> //header files
#include <string>


using namespace std;




int main()
{
	//initializing an integer number
	int inval = 25;
	
	//initializing a floating number
	float flval = 15.03;


	//changing int to string
	string strng_i= to_string (inval);


	// changing float to string
	string strng_f = to_string (flval);


	// printing the converted strings
	cout << "In string, the integer is: ";
	cout << strng_i << endl;
	cout << "In string, the float is: ";
	cout << strng_f << endl;


	return 0;
}

Output:

In string, the integer is: 25
In string, the float is: 15.030000
Time Complexity: O(n)
Auxiliary Space: O(n)

Third approach:  Boost Lexical Cast:

Similar to how string conversion works, the "lexical cast()" method stays the same, but the argument list changes when using "boost lexical cast," becoming "lexical_cast(num_var)".

C++ Program:

#include <boost/lexical_cast.hpp> //header files
#include <iostream>
#include <string> 
using namespace std;




int main()
{
	//initializing a floating number
	float fl_val = 17.6;


	//initializing an integer number
	int in_val = 21;


	// changing float to string
	string strng_f = boost::lexical_cast<string>(fl_val);


	//changing int to string
	string strng_i = boost::lexical_cast<string>(in_val);


	// printing the converted strings
	cout << "In string, the float is: ";
	cout << strng_f << endl;
	cout << "In string, the integer is: ";
	cout << strng_i << endl;


	return 0;
}

Output:

In string, the float is: 17.6
In string, the integer is: 21
Time Complexity: O(n)
Auxiliary Space: O(n)



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