Strings

So far, we've learned that char is used to store a single character.

But what if we want to store a word or a sentence like "Hello"?

That's where strings come in.

What is a String?

A string is a sequence of characters stored in a character array and terminated by a null character (\0) in C.

For example:

char name[] = "John";

Internally, it is stored like:

J   o   h   n   \0

The \0 marks the end of the string.

Declaring a String

Since C doesn't have a separate built-in string data type, strings are stored using char arrays.

char name[20];

This creates a character array that can hold a string, including its terminating \0.

We can also initialize it directly:

char name[] = "John";

Printing a String

We use %s with printf() to display a string.

char name[] = "John";

printf("%s", name);

Output:

John

Taking String Input

We can use scanf() to read a string:

char name[20];

scanf("%19s", name);

If the user enters:

John

the program stores "John" in name.

Notice that we don't use & before name here because the array name already represents the address of its first element in this context.

scanf("%s", ...) stops reading when it encounters whitespace, so it cannot read a full sentence containing spaces.

For example, if the user enters:

John Smith

only John would be read.

Reading a Full Line

To read a string containing spaces, fgets() is generally a safer choice:

char name[50];

fgets(name, sizeof(name), stdin);

This can read input such as:

John Smith

We'll explore fgets() and string input in more detail when we study input functions.

String Functions

C provides several useful functions for working with strings through the <string.h> header.

Example:

#include <stdio.h>
#include <string.h>

int main()
{
    char name[] = "John";

    printf("%zu", strlen(name));

    return 0;
}

Output:

4

strlen() returns the number of characters, not including the terminating \0.

Character vs String

This is an important difference:

char grade = 'A';       // Character
char name[] = "John";   // String

A character uses single quotes, while a string uses double quotes.

'A'      → Character
"John"   → String

In Simple Words

A string in C is a sequence of characters stored in a character array and ending with \0.

For example:

char name[] = "John";

Understanding strings is important because they are used everywhere—from names and messages to text processing and user input.