Strings in C++

A string is a sequence of characters. In C++, strings can be handled in two ways: using C-style character arrays (from the C language) or using the C++ string class from the <string> header — which is much easier and more powerful.

C++ String Class

The string class is the modern and recommended way to work with text in C++. It handles memory automatically and provides many built-in functions.

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

int main() {
    string city = "Mumbai";
    cout << "City: " << city << endl;
    return 0;
}

Output:

City: Mumbai

String Input — cin and getline

cin reads only up to the first space. Use getline() to read full lines including spaces.

string name;
cout << "Enter full name: ";
getline(cin, name);
cout << "Hello, " << name << "!" << endl;

Sample Run:

Enter full name: Ravi Kumar
Hello, Ravi Kumar!

String Length — .length() or .size()

string word = "Programming";
cout << "Length: " << word.length() << endl;

Output:

Length: 11

Accessing Individual Characters

string s = "Hello";
cout << s[0] << endl;   // H
cout << s[4] << endl;   // o

String Concatenation

Two strings can be joined using the + operator:

string first = "Good";
string second = " Morning";
string message = first + second;
cout << message << endl;

Output:

Good Morning

Common String Functions

Substring Extraction

string text = "Hello World";
string part = text.substr(6, 5);   // start at index 6, take 5 chars
cout << part << endl;

Output:

World

Finding a Substring

string sentence = "C++ is powerful";
int pos = sentence.find("powerful");

if (pos != string::npos) {
    cout << "Found at index: " << pos << endl;
} else {
    cout << "Not found" << endl;
}

Output:

Found at index: 7

Converting String to Number and Vice Versa

#include <string>
using namespace std;

// String to integer
string numStr = "42";
int num = stoi(numStr);
cout << num + 8 << endl;   // 50

// Integer to string
int val = 100;
string s = to_string(val);
cout << s + " rupees" << endl;  // "100 rupees"

Comparing Strings

string a = "apple";
string b = "banana";

if (a == b) {
    cout << "Same" << endl;
} else {
    cout << "Different" << endl;
}

Output:

Different

Iterating Over a String

string name = "Code";
for (char c : name) {
    cout << c << "-";
}

Output:

C-o-d-e-

Key Takeaways

• Use the string class from <string> for easy string handling.
• getline() reads full lines including spaces.
• Strings support concatenation with + and comparison with ==.
• Built-in functions like substr(), find(), and replace() make string manipulation easy.
• Use stoi() and to_string() to convert between strings and numbers.