Strings Manipulation

Manipulate strings using '<string>' STL in C++.

<string>

In C++, the Standard Template Library (STL) provides a variety of powerful tools for working with strings. The primary class for string manipulation in C++ is 'std::string', which is part of the '<string>' header. Here is simple the way to create a string using STL:

cpp Copy Code
#include<iostream>
#include<string>

int main() {
    // Creating a string
    std::string myString = "Hello, Friend!";
    std::cout << "String: " << myString << std::endl;
    return 0;
}
Output:
String: Hello, Friend!

Common operations using the '<string>' STL in C++:

1. Concatenation:

std::string str3 = str1 + str2;  // Concatenates two strings
str1 += "Hello";                  // Appends a string to another

2. Accessing Characters:

char ch = str1[0];                 // Accesses the character at index 0
char firstChar = str1.front();      // Gets the first character
char lastChar = str1.back();        // Gets the last character

3. String Length:

int length = str1.length();        // Gets the length of the string

4. Comparisons:

if (str1 == str2)                  // Checks if two strings are equal
if (str1.compare(str2) == 0)       // Compares two strings lexicographically

5. Finding Substrings:

std::string substr = str1.substr(1, 3);

Extracts a substring starting at index 1 and of length 3.

6. Insertion and Erasure:

str1.insert(2, "XYZ");             // Inserts "XYZ" at index 2
str1.erase(1, 3);                   // Erases 3 characters starting at index 1

7. Conversion to C-style Strings:

const char* cstr = str1.c_str();

Gets a pointer to the C-style string representation.

8. Empty Check:

if (str1.empty()) // Checks if the string is empty

9. Iterating Through Characters:

for (char c : str1) {
    // Iterate through each character in the string
}

10. Resizing:

str1.resize(10);

Resizes the string to have a length of 10.

* These are just a few examples of the many operations you can perform using the '<string>' STL in C++. The header provides a comprehensive set of functions for efficient string manipulation.

Let's create a program to demonstrate all the avobe STL operations mentioned:

cpp Copy Code
#include<iostream>
#include<string>

 int main() {
 // Declaration and Initialization
 std::string str1 = "Hello, ";
 std::string str2 = "Friend!";
 
 // Concatenation
 std::string str3 = str1 + str2;
 
 // Accessing Characters
 char ch = str1[0];
 char firstChar = str1.front();
 char lastChar = str1.back();
 
 // String Length
 int length = str1.length();
 
 // Comparisons
 bool isEqual = (str1 == str2);
 bool isLexicEql = (str1.compare(str2) == 0);
 
 // Substring
 std::string substr = str1.substr(1, 3);
 
 // Finding Substrings
 size_t pos = str1.find("lo");
 
 // Insertion and Erasure
 str1.insert(6, "Beautiful ");
 str1.erase(3, 2);
 
 // Conversion to C-style Strings
 const char* cstr = str1.c_str();
 
 // Empty Check
 bool isEmpty = str1.empty();
 
 // Iterating Through Characters
 for (char c : str1) {
 std::cout << c << " ";
 }
 
 std::cout << "\n";
 
 // Resizing
 str1.resize(10);
 
 // Output Results
 std::cout << "Concatenated String: " << str3 << "\n";
 std::cout << "Accessed Character: " << ch << "\n";
 std::cout << "First Character: " << firstChar << "\n";
 std::cout << "Last Character: " << lastChar << "\n";
 std::cout << "String Length: " << length << "\n";
 std::cout << "Are Strings Equal? " << std::boolalpha << isEqual << "\n";
 std::cout << "Strings Lexicographically Equal? " << isLexicEql << "\n";
 std::cout << "Substring: " << substr << "\n";
 std::cout << "Substring Position: " << pos << "\n";
 std::cout << "Inserted and Erased String: " << str1 << "\n";
 std::cout << "C-style String: " << cstr << "\n";
 std::cout << "Is String Empty? " << isEmpty << "\n";
 
 return 0;
 }
Output:
H e l , B e a u t i f u l     
Concatenated String: Hello, Friend!       
Accessed Character: H
First Character: H
Last Character:  
String Length: 7
Are Strings Equal? false
Strings Lexicographically Equal? false
Substring: ell
Substring Position: 3
Inserted and Erased String: Hel,Beauti
C-style String: Hel,Beauti
Is String Empty? false

* This program covers the mentioned operations and prints the results for each operation. Feel free to modify it or expand upon it based on your specific needs.

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