C++ - STRINGS

A String is a collection of letters/alphabets. It can be a word or a sentence.

The Data Type for String is string.

Declaring a String with Double Quotes ""

When C++ finds data inside Double Quotes "" and of datatype string. It creates a String type variable for that value.

string x = "Hello World";

Example :

#include <iostream>
using namespace std;

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

Output :

Hello World

And that's all! You have a String in place.

Let us understand the next example with the below code.

Example :

#include <iostream>
using namespace std;

int main() {

    string x;
    x = "Hello World";
   	cout << x;
    
    return 0;
}

Output :

Hello World

Just note that we have not initialised the variable x. We have just declared it.

string x;

So that an empty variable x would be created that would only hold a String.

Then in the next line, we have assigned the value Hello World to the variable x.

x = "Hello World";

Well ! We have declared a String type variable and assigned it later.

Accessing the characters of a String

Example :

#include <iostream>
using namespace std;

int main() {

    string x = "Hello"; 
    char y = x[1];
   	cout << y;
   	
    return 0;
}

Output :

So, we have a string Hello,

string x = "Hello";

And we have assigned Hello to a variable x.

Let us elaborate more, on how the String Hello is stored in the variable x.

So, just for the sake of understanding, you can assume the variable x is divided into 5 parts to store Hello.

Now, if you check from the front, the count starts from 0 and ends with 4.

So, if we look at the next line in the code,

char y = x[1];

We are trying to access the 2nd location,

So, x[1] is referring to the 2nd location where e is stored.

char y = x[1];

And we have assigned e to the variable y.

Note : The square brackets [] are used with the string type variable to get the variable at that position(i.e. x[1] refers to the 2nd location that contains e).

Now, if you look at the print statement,

cout << y;

The value of y is printed as output.

Output :

In the earlier examples, we have seen the + sign. And as we know, + is used for addition of two numbers.

Well ! In C++, + can be used to join two Strings as well.

Concatenation of Strings

Say, we have two Strings, Hello and World. And we want to join/concatenate them into one String, HelloWorld.

Let us solve it with the below example.

Example :

#include <iostream>
using namespace std;

int main() {

    string x = "Hello";
    string y = "World";
    string z = x + y;
    cout << z;
    
    return 0;
}

Output :

HelloWorld

So, we have stored the String Hello in x.

string x = "Hello";

And, stored the String World in y.

string y = "World";

And used the + operator to join/concatenate Hello and World.

string z = x + y;

And store the concatenated value in z.

So, + is not just used to add two numbers but + is also used to join/concatenate two Strings.

How to find the length of a String?

size()

size() is used to return the length of a String.

Example :

#include <iostream>
using namespace std;

int main() {
    
    string x = "Hello";
    cout << "The length of the String is : " << x.size();
    
    return 0;
}

Output :

The length of the String is : 5

length()

length() is used to return the length of a String.

Example :

#include <iostream>
using namespace std;

int main() {
    
    string x = "Hello";
    cout << "The length of the String is : " << x.length();
    
    return 0;
}

Output :

The length of the String is : 5

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