C Strings: The Complete Guide For Beginners 2021

C Strings: The Complete Guide For Beginners 2021

This C Strings are one-dimensional arrays of characters with the null character ‘0’ at the end. The characters that make up the string are followed by a null in a null-terminated string.

The declaration and initialization that follow produce a string that contains the word “Hello.” The character array holding the string must be one larger than the number of characters in the word “Hello” to accommodate the null character at the conclusion of the array.

If you follow the array initialization rule, you can write the following statement.

The memory representation of the above described string in C/C++ is as follows:

In reality, the null character does not belong at the end of a string constant. When the C compiler initializes the array, it places the ‘0’ at the end of the string. Let’s see whether we can print the above-mentioned string.

What is the best way to declare a string?

You can declare strings in the following way:

We’ve declared a 5-character string here.

What is the best way to start a string?

Strings can be initialized in a variety of ways.

Assigning Values to Strings

In C, arrays and strings are second-class citizens; once declared, they do not support the assignment operator. As an example,

Read String from the user

To read a string, use the scanf() function.

The scanf() function examines a string of characters until it comes to a whitespace character (space, newline, tab, etc.).

Example of scanf() to read a string

When the preceding code is compiled and run, the following result is obtained:

Despite the fact that adones evanz was typed into the application, the name string simply included “adones.” It’s because following adones, there was a blank area.

Also, instead of using &name with scanf, we utilized the code name ().

Because name is a char array, we know that in C, array names decay to pointers.

As a result, we don’t need to use & because the name in scanf() already points to the location of the first element in the string.

How do you read a single line of text?

To read a line of string, use the fgets() function. You may also use puts() to show the string.

Example of fgets() and puts()

When the preceding code is compiled and run, the following output is in the image below

To read a string from the user, we utilized the fgets() function.

/ read string fgets(name, sizeof(name), stdlin);

The result of sizeof(name) is 30. As a result, we can only accept 30 characters as input, which is the length of the name string.

We used puts(name); to output the string.

Note that the gets() function can also be used to receive user input. However, it is no longer included in the C standard.

It’s because gets() allows you to provide any character length. As a result, a buffer overflow could occur.

Passing Strings to Functions

Strings are supplied to functions in the same manner as arrays are. Find out more about how to pass arrays to a function.

Example of Passing string to a Function

When the preceding code is compiled and run, the following output is in the image below

Strings and Pointers

String names are “decayed” to pointers in the same way as arrays are. As a result, you can alter string elements with pointers. Before proceeding with this example, we recommend that you review C Arrays and Pointers.

Example of Strings and Pointers

Output

String Functions That Are Frequently Used

  • strlen() is a function that determines the length of a string.
  • strcpy() is a function that copies a string to another.
  • strcmp() is a function that compares two strings.
  • strcat() is a function that joins two strings together.

C Strings Functions

You’ll learn how to manipulate strings in C using library functions like gets(), puts(), strlen(), and more in this article. You’ll learn how to acquire a string from a user and then manipulate it.

You must frequently alter strings in order to solve a problem. String manipulation can be done manually most of the time, if not all of the time, but this makes programming complex and huge.

To address this, the standard library “string.h” in C includes a significant number of string handling functions.

The following are a few regularly used string handling functions:

No.Function Purpose
1strcpy(s1, s2);Copies string s2 into string s1.
2strcat(s1, s2);Concatenates string s2 onto the end of string s1.
3strlen(s1);Returns the length of string s1.
4strcmp(s1, s2);Returns 0 if s1 and s2 are the same; less than 0 if s1<s2; greater than 0 if s1>s2.
5strchr(s1, ch);Returns a pointer to the first occurrence of character ch in string s1.
6strstr(s1, s2);Returns a pointer to the first occurrence of string s2 in string s1.

The “string.h” header file defines the string handling functions.

To run string handling functions, you must include the code below.

gets() and puts()

As described in the last chapter, the functions gets() and puts() are two string functions that take string input from the user and display it.

Example of gets() and puts():

When the preceding code is compiled and run, the following output is in the image below

Note Though the gets() and puts() functions deal with strings, they are both defined in the “stdio.h” header file.

C Strings Examples

Finding the Frequency of Characters in a String in C

You will learn how to find the frequency of a character in a string in this example.

To follow along with this example, you should be familiar with the following C programming concepts:

  • C Arrays
  • C Programming Strings

Calculate a Character’s Frequency

When the preceding code is compiled and run, the following output is in the image below

The string entered by the user is saved in str in this program.
The user is then prompted to enter the character whose frequency is being sought. This is saved in the ch variable.

Note: This application is case-sensitive, which means it distinguishes between uppercase and lowercase versions of the same alphabet.

Concatenation of two strings in C

You will learn how to manually concatenate two strings without using the strcat() function in this example.

To follow along with this example, you should be familiar with the following C programming concepts:

  • Arrays in C
  • C Programming Strings
  • C for Loop

The strcat() method is the finest technique to concatenate two strings in C programming, as you may know. In this example, however, we shall manually concatenate two strings.

Example of Concatenate Two Strings Without Using strcat()

When the preceding code is compiled and run, the following output is in the image below

Two strings, s1 and s2, are concatenated in this case, and the result is saved in s1.

It’s vital to remember that s1 must be long enough to hold the string after concatenation. If you don’t, you can receive surprising results.

Removes all characters except alphabets from a string in C

You will learn how to remove all characters from a string entered by the user except the alphabets in this example.

To follow along with this example, you should be familiar with the following C programming concepts:

  • Arrays in C
  • Strings in C Programming
  • C stands for loop.
  • Loop C while and do…while

Remove Characters in String Except Alphabets examples:

When the preceding code is compiled and run, the following output is in the image below

Summary

Strings are one-dimensional arrays of characters with the null character ‘0’ at the end. Declaration and initialization produce a string that contains the word “Hello”. The character array holding the string must be one larger than the number of characters in the word.

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