Home » C programming language

Strings in C Programming Language (With Examples)

Strings in C programming language: In this tutorial, we will learn about the strings in C, declaring, initializing, printing getting the length of the string, and many more with the help of examples. By Sneha Dujaniya Last updated : December 26, 2023

What are Strings?

Strings are mostly considered difficult by many beginners but trust me, Strings are no big deal. A string is nothing but a group of characters stored in a character array. Character arrays are used in programming languages to manipulate words and sentences.

A string is a constant in the form of the one-dimensional array of characters terminated by a null character which is \0. Example,

 char city[] = {'T', 'O', 'K', 'Y', 'O', '\0'};

Declaring String

The string is a character array. Thus, to declare a string, you need to create a character array with the maximum size of the string.

Syntax

char string_name[maximum_size];

Example

Declare a string to store a name.

char name[30];

Initialize String

There are multiple methods to initialize string.

1. Initialize string during declaration

You can initialize a string during declaration in the following ways:

char name1[30] = "Alvin Alexander";
char name2[] = "Alvin Alexander";
char name3[30] = {'A','l','v','i','n',' ','A','l','e','x','a','n','d','e','r'};
char name4[30] = {'A','l','v','i','n',' ','A','l','e','x','a','n','d','e','r'};

2. Initialize string by using strcpy() or memcpy()

You cannot directly assign a string by using the assignment (=) operator. You can initialize a string anywhere in the program after the declaration by using either strcpy() or memcpy() function.

strcpy(name, "Alvin Alexander");
memcpy(name, "Alvin Alexander", 15);

Printing String

To print a string in language, you can use printf() and puts() functions. The printf() function requires "%s" format specifier to display the string value whereas the puts() function just takes the string variable as an argument.

Example

#include <stdio.h>

int main() {
  // Declaring string 
  char name[] = "Alvin Alexander";

  // Printing string using printf()
  printf("The name is : %s\n", name);

  // Using puts()
  puts(name);

  return 0;
}

Output

The name is : Alvin Alexander
Alvin Alexander

Printing String Variable Size

To print the occupied memory size (in bytes) by a string variable, you can use the sizeof() operator.

Example

#include <stdio.h>

int main() {
  // Declaring string 
  char name[30] = "Alvin Alexander";

  // Printing string using printf()
  printf("The name is : %s\n", name);

  // Printing size of the variable
  printf("Variable name took %ld bytes in memory.", sizeof(name));

  return 0;
}

Output

The name is : Alvin Alexander
Variable name took 30 bytes in memory.

Getting String Length

There are two ways to get the string length: Using the strlen() method (which is a library function of string.h header), and by counting each character of the string using the loop (for that you can create a function to get the string length).

Example

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

// Function to get the length of string
int StringLength(const char str[])
{
    int i = 0, len = 0;
    while (str[i++] != '\0')
        len++;
    return len;
}

int main()
{
    // Declaring string
    char name[30] = "Alvin Alexander";

    // Printing string using printf()
    printf("The name is : %s\n", name);

    // Length of string using library function strlen()
    printf("The lenght is : %ld\n", strlen(name));
    // Length of string using our function StringLength()
    printf("The lenght is : %d\n", StringLength(name));

    return 0;
}

Output

The name is : Alvin Alexander
The lenght is : 15
The lenght is : 15

C Strings: More Examples

Now let us see some of the examples:

Example 1: Declare string and print character by character

#include <stdio.h>

int main() {
  //declaring string
  char city[] = "Tokyo";

  //loop counter
  int i = 0;

  //printing string one by one character
  while (i <= 4) {
    printf("%c", city[i]);
    i++;
  }
  return 0;
}

Output

Tokyo

Simple program, where we are treating the string as a character array and we use %c in printf() statement. Also, the length of the word is taken to be 4 because the value of the first element in an array is always assigned 0, as we all know already. But this solution is not profitable if we have a bigger string.

So, here is another way to do it:

Example 2: Declare string and print character by character till NULL not found

#include <stdio.h>

int main() {
  //declaring string
  char city[] = "Tokyo";

  //loop counter
  int i = 0;

  //printing string one by one character
  //till NULL ('\0') not found 
  while (city[i] != '\0') {
    printf("%c", city[i]);
    i++;
  }
  return 0;
}

Output

Tokyo

Example 3: Declaring string and printing as string (using "%s" format specifier)

#include <stdio.h>

int main() {
  //declaring string
  char city[] = "Tokyo";

  //print as string
  //using "%s" format specifier
  printf("%s", city);

  return 0;
}

Output

Tokyo

This was the simplest way to print a string using the general specification of %s.

Example 4: Reading string using scanf() function

#include <stdio.h>

int main() {
  //declaring string/character array
  char city[15];

  //read string 
  printf("Enter a city: ");
  scanf("%s", city);

  //printing string
  printf("Good Morning %s!", city);

  return 0;
}

Output

Enter a city: Mumbai
Good Morning Mumbai!

Here, the declaration char city[15] stores 15 bytes of memory under the array city[]. Whereas, the scanf() function fills the characters entered till the enter key is pressed by the user. After that, scanf() automatically adds a null character leaving the further memory blank.

Reading a string using scanf() or gets()?

Points to be kept in mind while using scanf():

1. The length of the string entered by the user should not exceed the value declared in the array since C compilers do not show any Array index out of bound error for this. It will simply result in the overwriting of important data.
2. Using scanf(), we can't enter a multi-word string, for example, "New York". This problem can be resolved by using the function gets() and puts() as shown below,

Use of gets() and puts()

#include <stdio.h>

int main() {
  //declaring string/character array
  char city[15];

  //read the string
  printf("Enter a city: ");
  gets(city);

  //printing the string 
  puts("Good Morning!");
  puts(city);

  return 0;
}

Output

Enter a city: New York
Good Morning!
New York

Here, puts() can display only one string at a time therefore, two puts() statements are used. Also, unlike printf(), it places the cursor automatically to the next line.

Though gets() can receive only one string at a time, still it is preferable as it can receive multi-word strings.

Author's note:

This was a basic of what strings actually are. In the next article, I will write about string manipulations and standard library string functions. For better understanding, practice these codes on your own by changing the values and outputs. I'm ready to help if the case of queries. Happy coding!