🔹 String Examples in C++

 

C++ provides the std::string class to handle text-based data efficiently.

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1️⃣ Basic Example of String in C++

📌 Declaring and displaying a string.

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

int main() {
    string str = "Hello, C++!";
    cout << str;
    return 0;
}

🔹 Output

Hello, C++!

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2️⃣ Addition using String

📌 Concatenating strings using + operator.

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

int main() {
    string str1 = "Hello";
    string str2 = " World";
    string result = str1 + str2;
    cout << "Concatenated String: " << result;
    return 0;
}

🔹 Output

Concatenated String: Hello World

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3️⃣ String Append in C++

📌 Appending a string using .append().

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

int main() {
    string str = "Hello";
    str.append(" C++");
    cout << str;
    return 0;
}

🔹 Output

Hello C++

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4️⃣ String Capacity Function in C++

📌 Checking the capacity of a string.

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

int main() {
    string str = "Hello";
    cout << "Length: " << str.length() << endl;
    cout << "Capacity: " << str.capacity() << endl;
    cout << "Max Size: " << str.max_size() << endl;
    return 0;
}

🔹 Output

Length: 5
Capacity: 15
Max Size: 1073741823

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5️⃣ String Character Change in C++

📌 Modifying a character in a string.

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

int main() {
    string str = "Hello";
    str[0] = 'M';
    cout << str;
    return 0;
}

🔹 Output

Mello

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6️⃣ String Concatenation in C++

📌 Using += operator for concatenation.

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

int main() {
    string str = "Hello";
    str += " World";
    cout << str;
    return 0;
}

🔹 Output

Hello World

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7️⃣ String Input Getline in C++

📌 Taking full-line input using getline().

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

int main() {
    string str;
    cout << "Enter a sentence: ";
    getline(cin, str);
    cout << "You entered: " << str;
    return 0;
}

🔹 Output

Enter a sentence: Hello C++ World
You entered: Hello C++ World

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8️⃣ String Length in C++

📌 Finding the length of a string.

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

int main() {
    string str = "C++ Programming";
    cout << "String Length: " << str.length();
    return 0;
}

🔹 Output

String Length: 16

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9️⃣ String Palindrome in C++

📌 Checking if a string is a palindrome.

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

bool isPalindrome(string str) {
    string rev = string(str.rbegin(), str.rend());
    return str == rev;
}

int main() {
    string str = "madam";
    if (isPalindrome(str))
        cout << "Palindrome";
    else
        cout << "Not a Palindrome";
    return 0;
}

🔹 Output

Palindrome

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🔟 Remove Duplicate String in C++

📌 Removing duplicate characters.

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

string removeDuplicates(string str) {
    unordered_set<char> seen;
    string result;
    for (char ch : str) {
        if (seen.find(ch) == seen.end()) {
            seen.insert(ch);
            result += ch;
        }
    }
    return result;
}

int main() {
    string str = "programming";
    cout << "After removing duplicates: " << removeDuplicates(str);
    return 0;
}

🔹 Output

After removing duplicates: progamin

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1️⃣1️⃣ String Resize in C++

📌 Resizing a string.

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

int main() {
    string str = "Hello World";
    str.resize(5);
    cout << str;
    return 0;
}

🔹 Output

Hello

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1️⃣2️⃣ String Reverse without using Function

📌 Manually reversing a string.

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

int main() {
    string str = "hello";
    int n = str.length();
    for (int i = 0; i < n / 2; i++)
        swap(str[i], str[n - i - 1]);

    cout << "Reversed String: " << str;
    return 0;
}

🔹 Output

Reversed String: olleh

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1️⃣3️⃣ Sentence Case Example using String

📌 Capitalizing the first letter.

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

string sentenceCase(string str) {
    if (!str.empty())
        str[0] = toupper(str[0]);
    return str;
}

int main() {
    string str = "hello world!";
    cout << sentenceCase(str);
    return 0;
}

🔹 Output

Hello world!

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1️⃣4️⃣ Swapping String in C++

📌 Swapping two strings.

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

int main() {
    string str1 = "Apple", str2 = "Banana";
    cout << "Before Swap: " << str1 << " & " << str2 << endl;
    str1.swap(str2);
    cout << "After Swap: " << str1 << " & " << str2 << endl;
    return 0;
}

🔹 Output

Before Swap: Apple & Banana
After Swap: Banana & Apple

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📌 Summary

✔ Strings in C++ are mutable and support various functions.
✔ Use .append(), +, or += for concatenation.
✔ Use .length() or .size() to find the length.
✔ Use .resize() to adjust the string size.
✔ Use getline(cin, str) for full-line input.
✔ swap(), reverse(), and removeDuplicates() are useful manipulations.

🚀 Let me know if you need more examples! 🔥