String Manipulation Techniques in C++

1. Introduction

In this tutorial, you'll learn how to manipulate strings in C++. C++ provides a variety of built-in functions that allow us to process and format strings effectively.

By the end of this tutorial, you'll be able to:

• Understand the basic concepts of string manipulation.
• Use built-in string functions to manipulate strings.
• Implement these techniques in your own programs.

Prerequisites: Basic knowledge of C++ is required. Familiarity with data types, particularly strings, would be beneficial.

2. Step-by-Step Guide

C++ strings are stored as a collection of characters. This allows us to perform various operations on them, like concatenation, comparison, and more.

Let's dive into some of the common string manipulation techniques.

2.1 Concatenation

Concatenation in C++ is done using the + operator.

string str1 = "Hello";
string str2 = "World";
string str3 = str1 + " " + str2;  // Concatenation
cout << str3;  // Outputs: Hello World

2.2 Comparison

C++ allows us to compare strings using the == (equality) and != (inequality) operators.

string str1 = "ABC";
string str2 = "ABC";
if (str1 == str2) {
    cout << "Strings are equal.";  // This will be printed
} else {
    cout << "Strings are not equal.";
}

2.3 Substring

We can extract a substring from a string using the substr() function. It takes two parameters: the starting index and the length of the substring.

string str = "Hello, World!";
string sub = str.substr(7, 5);  // Get substring starting from index 7 and of length 5
cout << sub;  // Outputs: World

Remember, string indices start from 0 in C++.

3. Code Examples

Let's look at some practical examples.

3.1 String Length

This example shows how to find the length of a string.

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

int main() {
    string str = "Hello, World!";
    cout << "Length of string is " << str.length();  // Outputs: Length of string is 13
    return 0;
}

3.2 String Replacement

This example shows how to replace a part of the string.

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

int main() {
    string str = "Hello, World!";
    str.replace(7, 5, "C++");  // Replace 'World' with 'C++'
    cout << str;  // Outputs: Hello, C++!
    return 0;
}

4. Summary

In this tutorial, we've covered basic string manipulation techniques in C++, including concatenation, comparison, and substring extraction. Practice these techniques to get a better grip on them.

As a next step, you can explore more advanced string manipulation techniques and built-in functions in C++. You can refer to the C++ documentation for more details.

5. Practice Exercises

1. Write a program that concatenates two strings input by the user.
2. Write a program that compares two strings to check if they are equal.
3. Write a program that extracts a substring from a given string.

Here are the solutions for the exercises:

1. Concatenation:

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

int main() {
    string str1, str2;
    cout << "Enter first string: ";
    cin >> str1;
    cout << "Enter second string: ";
    cin >> str2;
    string result = str1 + str2;
    cout << "Result: " << result;
    return 0;
}

1. Comparison:

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

int main() {
    string str1, str2;
    cout << "Enter first string: ";
    cin >> str1;
    cout << "Enter second string: ";
    cin >> str2;
    if (str1 == str2) {
        cout << "Strings are equal.";
    } else {
        cout << "Strings are not equal.";
    }
    return 0;
}

1. Substring:

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

int main() {
    string str;
    int start, length;
    cout << "Enter a string: ";
    cin >> str;
    cout << "Enter starting index and length for substring: ";
    cin >> start >> length;
    string sub = str.substr(start, length);
    cout << "Substring: " << sub;
    return 0;
}

Remember to keep practicing and experimenting with different scenarios. Happy coding!