C++ String Operations

Declaration and Initialization:

#include <iostream>
#include <string>

int main() {
    // Declaration and initialization of a string
    std::string greeting = "Hello, World!";

    // Displaying the string
    std::cout << greeting << std::endl;

    return 0;
}

In C++, strings are sequences of characters represented by the std::string class. Strings are more flexible than character arrays and provide several built-in functions for string manipulation.

String Input/Output:

#include <iostream>
#include <string>

int main() {
    std::string name;

    // Input
    std::cout << "Enter your name: ";
    std::cin >> name;

    // Output
    std::cout << "Hello, " << name << "!" << std::endl;

    return 0;
}

You can use the standard input/output operations with strings.

Concatenation:

#include <iostream>
#include <string>

int main() {
    std::string first = "Hello";
    std::string second = "World";

    // Concatenation using the + operator
    std::string result = first + ", " + second + "!";

    // Displaying the result
    std::cout << result << std::endl;

    return 0;
}

Strings can be concatenated using the + operator or the append function.

String Length:

#include <iostream>
#include <string>

int main() {
    std::string message = "Hello, World!";

    // Using length() function
    std::cout << "Length of the string: " << message.length() << std::endl;

    return 0;
}

The length() function or size() function can be used to get the length of a string.

String Access:

#include <iostream>
#include <string>

int main() {
    std::string greeting = "Hello, World!";

    // Accessing characters using []
    std::cout << "First character: " << greeting[0] << std::endl;
    std::cout << "Third character: " << greeting[2] << std::endl;

    return 0;
}

Individual characters in a string can be accessed using the [] operator.

String Comparison:

#include <iostream>
#include <string>

int main() {
    std::string str1 = "Hello";
    std::string str2 = "World";

    // Comparing strings
    if (str1 == str2) {
        std::cout << "Strings are equal." << std::endl;
    } else {
        std::cout << "Strings are not equal." << std::endl;
    }

    return 0;
}

Strings can be compared using relational operators (==, !=, <, >, <=, >=).

String Manipulation:

#include <iostream>
#include <string>

int main() {
    std::string sentence = "The quick brown fox jumps over the lazy dog";

    // Extracting a substring
    std::string word = sentence.substr(10, 5); // Extract "brown"

    // Finding the position of a substring
    size_t position = sentence.find("fox"); // Find the position of "fox"

    // Replacing a substring
    sentence.replace(position, 3, "cat"); // Replace "fox" with "cat"

    // Displaying the modified string
    std::cout << sentence << std::endl;

    return 0;
}

C++ provides a rich set of string manipulation functions through the std::string class. Familiarizing yourself with these functions allows you to work effectively with strings in C++ programs.