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++ 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++ 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++ Array program in C++ 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++ C++ vardiac() function Difference between Two Sets in C++ Difference between Exit and Return Structured Binding in C++ Differences between Local and Global Variable Bitwise Operator vs Logical Operator Difference between OOP and POP in C++ Fork in C++ Functors in C++ 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++ Lambda Expression in C++ Pattern programs in C++ Roadmap to C++ Programming Substring in C++ Virtual base class in C++

C++ String

string is a collection of characters. C++ programming language supports both C string as well as standard C++ library string. In C++, string is an object of std::string class.

C Style String

The C style string of C language is also supported in C++ programming language. C string is an array of char and terminated by a null character '\0'.

String Declaration

There are two different way to declare C style string in C++ programming: 1. Through array of character.
char stringName[5];
2. Through pointers.
char *stringName;

String Initialization

String initialization is done by passing character in character (char) array end with null (\0). String initialization is also done by passing the value in string name within double inverted comma (" ");
char  stringName[8]={'w','e','l','c','o','m','e','\0'};
char stringName[]="welcome";

Memory Representation of String

C++ String Example 1

#include<iostream>  
using namespace std;  
int main(){  
    char message1[8]={'w','e','l','c','o','m','e','\0'};  
    char message2[]="programmer";  
    cout<<"print message1 :"<<message1<<endl;  
    cout<<"print message2 :"<<message2;  
    return 0;  
}
Output:
print message1 :welcome
print message2 :programmer

String function used in C as well as C++

Function Example Description
strlen() strlen(s1) Return length of string s1.
strcmp() strcmp(s1,s2) Compare string s1 and
strcpy() strcpy(s1,s2) Copy string s2 into string s1.
strcat() strcat(s1,s2) Concatenate string s2 at the end of string s1.
strchr() strchr(s1,ch) Search character ch in string s1.
strstr() strstr(s1,s2) Search string s2 in string s1.

C++ String Example 2

#include <iostream>  
#include <cstring>  
using namespace std;  
int main () {  
   char s1[10] = "Hello";  
   char s2[10] = "World";  
   char ch='l';  
   char s3[10];  
   int  len ;  
   // lenghth of s1  
   len = strlen(s1);  
   cout << "strlen(s1) : " << len << endl;  
   // copy s1 into s3  
   strcpy( s3, s1);  
   cout << "strcpy( s3, s1) : " << s3 << endl;  
   // comperesion s1 and s2  
    if (strcmp(s1,s2)==true){  
        cout<<"strcmp(s1,s2) :"<< "string are equal"<<endl;  
    }  
    else{  
        cout<<"strcmp(s1,s2) :"<<"string are not equal return :
"<< strcmp(s1,s2)<<endl;  
    }  
   // concatenates s1 and s2  
   strcat( s1, s2);  
   cout << "strcat( s1, s2): " << s1 << endl;  
    // search ch in s2  
    if (strchr(s2, ch)){  
        cout << ch << " is present in :" << s2 << endl;  
    }  
    else{  
        cout << ch << " is not present in :" << s2 << endl;  
    }  
    //search s3 in s1      
    if (strstr(s1, s3)){  
        cout << s3 << " is present in :" << s1 << endl;  
    }  
    else{  
        cout << s3 << " is not present in :" << s1 << endl;  
    }  
   return 0;  
}
Output:
strlen(s1) : 5
strcpy( s3, s1) : Hello
strcmp(s1,s2) :string are not equal return :-15
strcat( s1, s2): HelloWorld
l is not present in :
Hello is present in :HelloWorld

C++ Standard Library String

C++ provides a string class to overcome the complexity and inefficiency of using C style string in C++ programming. C++ uses standard library <string> to handle all manipulation done over string object.

C++ String Example 3

#include<iostream>  
#include<string>  
using namespace std;  
int main(){  
    string str1= "welcome";  
    string str2;  
    cout<<"Enter string"<<endl;  
    cin>>str2;  
    cout<< str1<< endl;  
    cout<<"Your enter string is :"<< str2;  
    return 0;  
}
Output:
Enter string
programmer
welcome
Your enter string is : programmer
In the above program <string> is the standard library that handles string manipulation and string in main() function is string class. In C++, cin and >> operator read only one word of a string, the compiler treats space as the termination of string provided in string as value. C++ string class supports many member functions, constructors and operators for manipulating string objects.

C++ String functions

Function Description
size() Return the number of characters in the string
length() Return the number of elements in a string
capacity() Gives the total elements that can be stored
max_size() Gives the maximum possible size of a string of string object
insert() Insert character at a specific location
replace() Replace specific character within a given string
erase() Removes characters as specified
append() Append a part of the string to another string
copy() Copy sequence of character from string
compare() Compare string against the invoking string
swap() Swap value of two string
getline() Read a line of string
C++ string also uses cin.get(ch) member function of istream class defined in <iostream> the member function cin.get(ch) reads the next character, even if it is a space, from the input and assigns it to the variable ch.

String Example 4

This program illustrate the use of size(), length()capacity()max_size() of string function.
#include <iostream>  
#include <string>  
using namespace std;  
int main ()  
{  
  string str="String program";  
  cout << "size: " << str.size() << endl;  
  cout << "length: " << str.length() << endl;  
  cout << "capacity: " << str.capacity() << endl;  
  cout << "max_size: " << str.max_size() << endl;  
  return 0;  
}
Output:
size: 14
length: 14
capacity: 15
max_size: 9223372036854775807

String Example 5

This program illustrate the use of insert()replace()erase() of string function.
#include <iostream>  
#include <string>  
using namespace std;  
int main ()  
{  
  string str;  
  string str1="first string";  
  string str2="second hello";  
  string str3="third welcome";  
  str.insert(0,str1);  
  str1.insert(6,str2,7,11);  
  cout << "after insert str: " << str << endl;  
  cout<< "after insert str1: " << str1<< endl;  
  str2.replace(7,5,str3);  
  cout<<"after replace str2: "<< str2<< endl;  
  str3.erase(2,6);  
  cout<<"afrer erase str3: "<<str3<< endl;  
  return 0;  
}
Output:
after insert str: first string
after insert str1: first hellostring
after replace str2: second third welcome
after erase str3: thlcome

String Example 6

This program illustrates the use of cin.get() of string function.
#include <iostream>  
using namespace std;  
int main()  
{  
    char ch[10];  
    cout<<"Enter char string  :";  
    cin.get(ch, 10);  
    cout << "Your char string is :" << ch << endl;  
    return 0;  
}
Output:
Enter char string :welcome
Your char string is :welcome
In the above program parameters passed in cin.get(ch,10) function represents variable name and size of variable respectively.

String Example 7

This program illustrates the use of getline() of string function.
#include <iostream>  
using namespace std;  
int main()  
{  
    string str;  
    cout<<"Enter string  :";  
    getline(cin,str);  
    cout << "Your string is :" << str << endl;  
    return 0;  
}
Output:
Enter string :welcome programmer
Your string is :welcome programmer
getline() function take input stream cin in the first parameter and string object (str) in the second parameter. In C++ it is prefer to use getline() function instead of using cin>> and cin.get().



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