Strings in C++

What are Strings?

A string is a sequence of characters. In C++, you can use the string class from the <string> library.

Declaring a String

Syntax: string variable_name = "value";

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

int main() {
    string message = "Hello, World!";
    cout << message;
    return 0;
}
            

Using getline()

Syntax: getline(cin, variable_name);
Used to read an entire line, including spaces.

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

int main() {
    string fullName;
    cout << "Enter your full name: ";
    getline(cin, fullName);
    cout << "Hello, " << fullName << "!";
    return 0;
}
            

Using cin.ignore()

Syntax: cin.ignore();
Clears the input buffer, useful after using cin before getline().

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

int main() {
    int age;
    string name;

    cout << "Enter your age: ";
    cin >> age;
    cin.ignore(); // Clears input buffer

    cout << "Enter your name: ";
    getline(cin, name);

    cout << "Hello, " << name << "! You are " << age << " years old.";
    return 0;
}
            

Finding String Length (length())

Syntax: string_variable.length();
Returns the number of characters in a string.

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

int main() {
    string text = "C++ is awesome!";
    cout << "Length: " << text.length(); // Output: 15
    return 0;
}
            

Getting Substrings (substr())

Syntax: string_variable.substr(start_index, length);
Extracts a portion of the string.

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

int main() {
    string text = "Programming";
    cout << text.substr(0, 4); // Output: "Prog"
    return 0;
}
            

Replacing Part of a String (replace())

Syntax: string_variable.replace(start_index, length, "new_value");
Replaces a section of a string with a new value.

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

int main() {
    string sentence = "I love Java!";
    sentence.replace(7, 4, "C++"); 
    cout << sentence; // Output: "I love C++!"
    return 0;
}
            

Inserting into a String (insert())

Syntax: string_variable.insert(index, "text_to_insert");
Adds a substring at the specified index.

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

int main() {
    string word = "Hello!";
    word.insert(5, " World");
    cout << word; // Output: "Hello World!"
    return 0;
}
            

Assigning a String (assign())

Syntax: string_variable.assign("new_value");
Assigns a new value to an existing string.

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

int main() {
    string text;
    text.assign("New text assigned!");
    cout << text;
    return 0;
}
            

Using String Arrays

Syntax: string array_name[size] = {"value1", "value2", ...};
Creates an array of strings.

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

int main() {
    string fruits[3] = {"Apple", "Banana", "Cherry"};
    cout << "Favorite fruit: " << fruits[1]; // Output: Banana
    return 0;
}
            

Concatenating Strings (+ or append())

Syntax:
string new_string = string1 + string2;
string1.append(string2);
Combines two strings together.

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

int main() {
    string firstName = "John";
    string lastName = "Doe";

    // Using +
    string fullName = firstName + " " + lastName;
    cout << fullName << endl;

    // Using append()
    string greeting = "Hello, ";
    greeting.append(firstName);
    cout << greeting;
    
    return 0;
}