What Is String in Data Structure in C?


Heather Bennett

When working with data structures in the C programming language, one important concept to understand is the string. A string is a sequence of characters that is used to represent text.

In C, strings are represented as arrays of characters and are terminated by a null character ‘\0’. In this article, we will explore the different aspects of strings in C and how they can be manipulated.

Declaring and Initializing Strings

To declare a string in C, you can use the char keyword followed by the name of the string and its size:

        char myString[20];

This declares a string named myString which can hold up to 19 characters (the last element is reserved for the null character). To initialize a string with a value, you can use the assignment operator (=) along with double quotes:

        char myString[20] = "Hello";

In this example, the string myString is initialized with the value “Hello”. It is important to note that the size of the array should be large enough to accommodate both the characters of the string and the null character.

Accessing Characters in a String

To access individual characters in a string, you can use array subscript notation. For example:

        char myString[20] = "Hello";
        printf("The first character is: %c\n", myString[0]);

In this code snippet, we access the first character of myString using index 0. The output will be ‘H’.

Modifying Strings

In C, strings are mutable, which means you can modify their contents. To do this, you can assign new values to individual characters or use string manipulation functions from the standard library. Here’s an example:

        char myString[20] = "Hello";
        myString[0] = 'J';
        printf("Modified string: %s\n", myString);

In this code snippet, we change the first character of myString from ‘H’ to ‘J’. The output will be “Jello”.

String Manipulation Functions

The C standard library provides several functions for manipulating strings. Some commonly used functions include:

  • strlen(): Returns the length of a string.
  • strcpy(): Copies one string to another.
  • strcat(): Concatenates two strings.
  • strcmp(): Compares two strings.

Here’s an example that demonstrates the usage of these functions:

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

        int main() {
            char source[] = "Hello";
            char destination[20];

            printf("Length: %d\n", strlen(source));
            strcpy(destination, source);
            printf("Copied string: %s\n", destination);

            strcat(destination, " world!");
            printf("Concatenated string: %s\n", destination);

            if (strcmp(source, destination) == 0) {
                printf("The strings are equal.\n");
            } else {
                printf("The strings are not equal.\n");

            return 0;

This code snippet demonstrates the usage of various string manipulation functions. It calculates the length of a string using strlen(), copies a string using strcpy(), concatenates two strings using strcat(), and compares two strings using strcmp().


In summary, a string in C is an array of characters terminated by a null character. It is used to represent text and can be manipulated using various string manipulation functions. Understanding how strings work in C is essential for working with text-based data in your programs.

Discord Server - Web Server - Private Server - DNS Server - Object-Oriented Programming - Scripting - Data Types - Data Structures

Privacy Policy