assignment array char c

• How to Initialize Char Array in C

Use {} Curly Braced List Notation to Initialize a char Array in C

Use string assignment to initialize a char array in c, use {{ }} double curly braces to initialize 2d char array in c.

This article will demonstrate multiple methods of how to initialize a char array in C.

A char array is mostly declared as a fixed-sized structure and often initialized immediately. Curly braced list notation is one of the available methods to initialize the char array with constant values.

It’s possible to specify only the portion of the elements in the curly braces as the remainder of chars is implicitly initialized with a null byte value.

It can be useful if the char array needs to be printed as a character string. Since there’s a null byte character guaranteed to be stored at the end of valid characters, then the printf function can be efficiently utilized with the %s format string specifier to output the array’s content.

Another useful method to initialize a char array is to assign a string value in the declaration statement. The string literal should have fewer characters than the length of the array; otherwise, there will be only part of the string stored and no terminating null character at the end of the buffer.

Thus, if the user will try to print the array’s content with the %s specifier, it might access the memory region after the last character and probably will throw a fault.

Note that c_arr has a length of 21 characters and is initialized with a 20 char long string. As a result, the 21st character in the array is guaranteed to be \0 byte, making the contents a valid character string.

The curly braced list can also be utilized to initialize two-dimensional char arrays. In this case, we declare a 5x5 char array and include five braced strings inside the outer curly braces.

Note that each string literal in this example initializes the five-element rows of the matrix. The content of this two-dimensional array can’t be printed with %s specifier as the length of each row matches the length of the string literals; thus, there’s no terminating null byte stored implicitly during the initialization. Usually, the compiler will warn if the string literals are larger than the array rows.

Founder of DelftStack.com. Jinku has worked in the robotics and automotive industries for over 8 years. He sharpened his coding skills when he needed to do the automatic testing, data collection from remote servers and report creation from the endurance test. He is from an electrical/electronics engineering background but has expanded his interest to embedded electronics, embedded programming and front-/back-end programming.

Related Article - C Array

• How to Copy Char Array in C
• How to Dynamically Allocate an Array in C
• How to Clear Char Array in C
• Array of Strings in C
• How to Print Char Array in C

How to Assign Values to an Array of Characters in C – C

The Problem:

When attempting to assign values to an array of characters in C, such as in the provided code, the error message "array type char[30] is not assignable" is encountered. This error occurs because arrays in C are not assignable directly.

The Solution:

Solution 1: using strcpy.

To assign values to a character array in C, you need to use a library function like strcpy. The strcpy function allows you to copy the contents of one string into another. In this case, you can use strcpy(word, "Jump"); to assign the string "Jump" to the character array "word".

Solution 2: Using memcpy

Another option is to use the memcpy function. The memcpy function allows you to copy a specified number of bytes from one memory location to another. In this case, you can use memcpy(word, "Jump", sizeof("Jump")); to assign the string "Jump" to the character array "word".

Conclusion:

In C, arrays of characters cannot be directly assigned values using the assignment operator. Instead, you need to use library functions like strcpy or memcpy to copy the desired string into the character array. By following these solutions, you can successfully assign values to character arrays in C.

• strcpy – C++ Reference
• memcpy – Linux Manual

[Fixed] C Error: “Array must be initialized with a brace enclosed initializer” – C

Understanding Format Specifier %02x in C Programming – C

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C String – How to Declare Strings in the C Programming Language

Computers store and process all kinds of data.

Strings are just one of the many forms in which information is presented and gets processed by computers.

Strings in the C programming language work differently than in other modern programming languages.

In this article, you'll learn how to declare strings in C.

Before doing so, you'll go through a basic overview of what data types, variables, and arrays are in C. This way, you'll understand how these are all connected to one another when it comes to working with strings in C.

Knowing the basics of those concepts will then help you better understand how to declare and work with strings in C.

Let's get started!

Data types in C

C has a few built-in data types.

They are int , short , long , float , double , long double and char .

As you see, there is no built-in string or str (short for string) data type.

The char data type in C

From those types you just saw, the only way to use and present characters in C is by using the char data type.

Using char , you are able to to represent a single character – out of the 256 that your computer recognises. It is most commonly used to represent the characters from the ASCII chart.

The single characters are surrounded by single quotation marks .

The examples below are all char s – even a number surrounded by single quoation marks and a single space is a char in C:

Every single letter, symbol, number and space surrounded by single quotation marks is a single piece of character data in C.

What if you want to present more than one single character?

The following is not a valid char – despite being surrounded by single quotation marks. This is because it doesn't include only a single character inside the single quotation marks:

'freeCodeCamp is awesome'

When many single characters are strung together in a group, like the sentence you see above, a string is created. In that case, when you are using strings, instead of single quotation marks you should only use double quotation marks.

"freeCodeCamp is awesome"

How to declare variables in C

So far you've seen how text is presented in C.

What happens, though, if you want to store text somewhere? After all, computers are really good at saving information to memory for later retrieval and use.

The way you store data in C, and in most programming languages, is in variables.

Essentially, you can think of variables as boxes that hold a value which can change throughout the life of a program. Variables allocate space in the computer's memory and let C know that you want some space reserved.

C is a statically typed language, meaning that when you create a variable you have to specify what data type that variable will be.

There are many different variable types in C, since there are many different kinds of data.

Every variable has an associated data type.

When you create a variable, you first mention the type of the variable (wether it will hold integer, float, char or any other data values), its name, and then optionally, assign it a value:

Be careful not to mix data types when working with variables in C, as that will cause errors.

For intance, if you try to change the example from above to use double quotation marks (remember that chars only use single quotation marks), you'll get an error when you compile the code:

As mentioned earlier on, C doesn't have a built-in string data type. That also means that C doesn't have string variables!

How to create arrays in C

An array is essentially a variable that stores multiple values. It's a collection of many items of the same type.

As with regular variables, there are many different types of arrays because arrays can hold only items of the same data type. There are arrays that hold only int s, only float s, and so on.

This is how you define an array of ints s for example:

First you specify the data type of the items the array will hold. Then you give it a name and immediately after the name you also include a pair of square brackets with an integer. The integer number speficies the length of the array.

In the example above, the array can hold 3 values.

After defining the array, you can assign values individually, with square bracket notation, using indexing. Indexing in C (and most programming languages) starts at 0 .

You reference and fetch an item from an array by using the name of the array and the item's index in square brackets, like so:

What are character arrays in C?

So, how does everything mentioned so far fit together, and what does it have to do with initializing strings in C and saving them to memory?

Well, strings in C are actually a type of array – specifically, they are a character array . Strings are a collection of char values.

How strings work in C

In C, all strings end in a 0 . That 0 lets C know where a string ends.

That string-terminating zero is called a string terminator . You may also see the term null zero used for this, which has the same meaning.

Don't confuse this final zero with the numeric integer 0 or even the character '0' - they are not the same thing.

The string terminator is added automatically at the end of each string in C. But it is not visible to us – it's just always there.

The string terminator is represented like this: '\0' . What sets it apart from the character '0' is the backslash it has.

When working with strings in C, it's helpful to picture them always ending in null zero and having that extra byte at the end.

Each character takes up one byte in memory.

The string "hello" , in the picture above, takes up 6 bytes .

"Hello" has five letters, each one taking up 1 byte of space, and then the null zero takes up one byte also.

The length of strings in C

The length of a string in C is just the number of characters in a word, without including the string terminator (despite it always being used to terminate strings).

The string terminator is not accounted for when you want to find the length of a string.

For example, the string freeCodeCamp has a length of 12 characters.

But when counting the length of a string, you must always count any blank spaces too.

For example, the string I code has a length of 6 characters. I is 1 character, code has 4 characters, and then there is 1 blank space.

So the length of a string is not the same number as the number of bytes that it has and the amount of memory space it takes up.

How to create character arrays and initialize strings in C

The first step is to use the char data type. This lets C know that you want to create an array that will hold characters.

Then you give the array a name, and immediatelly after that you include a pair of opening and closing square brackets.

Inside the square brackets you'll include an integer. This integer will be the largest number of characters you want your string to be including the string terminator.

You can initialise a string one character at a time like so:

But this is quite time-consuming. Instead, when you first define the character array, you have the option to assign it a value directly using a string literal in double quotes:

If you want, istead of including the number in the square brackets, you can only assign the character array a value.

It works exactly the same as the example above. It will count the number of characters in the value you provide and automatically add the null zero character at the end:

Remember, you always need to reserve enough space for the longest string you want to include plus the string terminator.

If you want more room, need more memory, and plan on changing the value later on, include a larger number in the square brackets:

How to change the contents of a character array

So, you know how to initialize strings in C. What if you want to change that string though?

You cannot simply use the assignment operator ( = ) and assign it a new value. You can only do that when you first define the character array.

As seen earlier on, the way to access an item from an array is by referencing the array's name and the item's index number.

So to change a string, you can change each character individually, one by one:

That method is quite cumbersome, time-consuming, and error-prone, though. It definitely is not the preferred way.

You can instead use the strcpy() function, which stands for string copy .

To use this function, you have to include the #include <string.h> line after the #include <stdio.h> line at the top of your file.

The <string.h> file offers the strcpy() function.

When using strcpy() , you first include the name of the character array and then the new value you want to assign. The strcpy() function automatically add the string terminator on the new string that is created:

And there you have it. Now you know how to declare strings in C.

To summarize:

• C does not have a built-in string function.
• To work with strings, you have to use character arrays.
• When creating character arrays, leave enough space for the longest string you'll want to store plus account for the string terminator that is included at the end of each string in C.
• Define the array and then assign each individual character element one at a time.
• OR define the array and initialize a value at the same time.
• When changing the value of the string, you can use the strcpy() function after you've included the <string.h> header file.

If you want to learn more about C, I've written a guide for beginners taking their first steps in the language.

It is based on the first couple of weeks of CS50's Introduction to Computer Science course and I explain some fundamental concepts and go over how the language works at a high level.

You can also watch the C Programming Tutorial for Beginners on freeCodeCamp's YouTube channel.

Thanks for reading and happy learning :)

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• C Data Types
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• C Functions
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• C Cheatsheet
• C Interview Questions
• Properties of Array in C
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• Strings in C

Array of Strings in C

• C Library - <string.h>
• C String Functions
• What is the difference between single quoted and double quoted declaration of char array?
• Array C/C++ Programs
• String C/C++ Programs

In C programming String is a 1-D array of characters and is defined as an array of characters. But an array of strings in C is a two-dimensional array of character types. Each String is terminated with a null character (\0). It is an application of a 2d array.

• var_name is the name of the variable in C.
• r is the maximum number of string values that can be stored in a string array.
• c is the maximum number of character values that can be stored in each string array.

Example: 

Below is the Representation of the above program 

We have 3 rows and 10 columns specified in our Array of String but because of prespecifying, the size of the array of strings the space consumption is high. So, to avoid high space consumption in our program we can use an Array of Pointers in C.

Invalid Operations in Arrays of Strings 

We can’t directly change or assign the values to an array of strings in C.

Here, arr[0] = “GFG”; // This will give an Error that says assignment to expression with an array type.

To change values we can use strcpy() function in C

Array of Pointers of Strings

In C we can use an Array of pointers. Instead of having a 2-Dimensional character array, we can have a single-dimensional array of Pointers. Here pointer to the first character of the string literal is stored.

Below is the C program to print an array of pointers:

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String and Character Array

String is a sequence of characters that are treated as a single data item and terminated by a null character '\0' . Remember that the C language does not support strings as a data type. A string is actually a one-dimensional array of characters in C language. These are often used to create meaningful and readable programs.

If you don't know what an array in C means, you can check the C Array tutorial to know about Array in the C language. Before proceeding further, check the following articles:

C Function Calls

C Variables

C Datatypes

For example: The string "home" contains 5 characters including the '\0' character which is automatically added by the compiler at the end of the string.

Declaring and Initializing a string variables:

String input and output:.

%s format specifier to read a string input from the terminal.

But scanf() function, terminates its input on the first white space it encounters.

edit set conversion code %[..] that can be used to read a line containing a variety of characters, including white spaces.

The gets() function can also be used to read character string with white spaces

String Handling Functions:

C language supports a large number of string handling functions that can be used to carry out many of the string manipulations. These functions are packaged in the string.h library. Hence, you must include string.h header file in your programs to use these functions.

The following are the most commonly used string handling functions.

strcat() function in C:

strcat() will add the string "world" to "hello" i.e ouput = helloworld.

strlen() and strcmp() function:

strlen() will return the length of the string passed to it and strcmp() will return the ASCII difference between first unmatching character of two strings.

strcpy() function:

It copies the second string argument to the first string argument.

Example of strcpy() function:

StudyTonight

strrev() function:

It is used to reverse the given string expression.

Code snippet for strrev() :

Enter your string: studytonight Your reverse string is: thginotyduts

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An array is a variable that can store multiple values. For example, if you want to store 100 integers, you can create an array for it.

How to declare an array?

For example,

Here, we declared an array, mark , of floating-point type. And its size is 5. Meaning, it can hold 5 floating-point values.

It's important to note that the size and type of an array cannot be changed once it is declared.

Access Array Elements

You can access elements of an array by indices.

Suppose you declared an array mark as above. The first element is mark[0] , the second element is mark[1] and so on.

Few keynotes :

• Arrays have 0 as the first index, not 1. In this example, mark[0] is the first element.
• If the size of an array is n , to access the last element, the n-1 index is used. In this example, mark[4]
• Suppose the starting address of mark[0] is 2120d . Then, the address of the mark[1] will be 2124d . Similarly, the address of mark[2] will be 2128d and so on. This is because the size of a float is 4 bytes.

How to initialize an array?

It is possible to initialize an array during declaration. For example,

You can also initialize an array like this.

Here, we haven't specified the size. However, the compiler knows its size is 5 as we are initializing it with 5 elements.

Change Value of Array elements

Input and output array elements.

Here's how you can take input from the user and store it in an array element.

Here's how you can print an individual element of an array.

Example 1: Array Input/Output

Here, we have used a  for loop to take 5 inputs from the user and store them in an array. Then, using another  for loop, these elements are displayed on the screen.

Example 2: Calculate Average

Here, we have computed the average of n numbers entered by the user.

Access elements out of its bound!

Suppose you declared an array of 10 elements. Let's say,

You can access the array elements from testArray[0] to testArray[9] .

Now let's say if you try to access testArray[12] . The element is not available. This may cause unexpected output (undefined behavior). Sometimes you might get an error and some other time your program may run correctly.

Hence, you should never access elements of an array outside of its bound.

Multidimensional arrays

In this tutorial, you learned about arrays. These arrays are called one-dimensional arrays.

In the next tutorial, you will learn about multidimensional arrays (array of an array) .

Table of Contents

• C Arrays (Introduction)
• Declaring an Array
• Access array elements
• Initializing an array
• Change Value of Array Elements
• Array Input/Output
• Example: Calculate Average
• Array Elements Out of its Bound

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2D character array-String array-Declaration and initialization

In this C Programming tutorial, we will discuss 2D character arrays in detail and will discuss how to declare, initialize and use 2D character arrays or String arrays.

Table of Contents

1. What is 2D character array in C?

We have successfully learned the basic concepts  and different  library functions  that C Programming offers. Another interesting concept is the use of 2D character arrays. In the previous tutorial, we already saw that string is nothing but an array of characters that ends with a ‘\0’ .

2D character arrays are very similar to 2D integer arrays . We store the elements and perform other operations in a similar manner. A 2D character array is more like a String array . It allows us to store multiple strings under the same name.

2. How to Declaration and Initialization a 2D character array?

A 2D character array is declared in the following manner:

The order of the subscripts is important during declaration. The first subscript [5] represents the number of Strings that we want our array to contain and the second subscript [10] represents the length of each String. This is static memory allocation. We are giving 5*10=50 memory locations for the array elements to be stored in the array.

Initialization of the character array occurs in this manner:

Let’s see the diagram below to understand how the elements are stored in the memory location:

The areas marked in green show the memory locations that are reserved for the array but are not used by the string. Each character occupies 1 byte of storage from the memory.

3. How to take 2D array Data input from user?

In order to take string data input from the user we need to follow the following syntax:

Here we see that the second subscript remains [0] . This is because it shows the length of the string and before entering any string the length of the string is 0 .

4. Printing the array elements

The way a 2D character array is printed is not the same as a 2D integer array. This is because we see that all the spaces in the array are not occupied by the string entered by the user.

If we display it in the same way as a 2D integer array we will get unnecessary garbage values in unoccupied spaces. Here is how we can display all the string elements:

This format will print only the string contained in the index numbers specified and eliminate any garbage values after ‘\0’ . All the string library functions that we have come across in the previous tutorials can be used for the operations on strings contained in the string array. Each string can be referred to in this form:

where [i] is the index number of the string that needs to be accessed by library functions.

5. Program to search for a string in the string array

Let’s implement a program to search for a string(a char array) entered by the user in a 2D char array or a string array (also entered by the user):

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Next: Unions , Previous: Overlaying Structures , Up: Structures   [ Contents ][ Index ]

15.13 Structure Assignment

Assignment operating on a structure type copies the structure. The left and right operands must have the same type. Here is an example:

Notionally, assignment on a structure type works by copying each of the fields. Thus, if any of the fields has the const qualifier, that structure type does not allow assignment:

See Assignment Expressions .

When a structure type has a field which is an array, as here,

structure assigment such as r1 = r2 copies array fields’ contents just as it copies all the other fields.

This is the only way in C that you can operate on the whole contents of a array with one operation: when the array is contained in a struct . You can’t copy the contents of the data field as an array, because

would convert the array objects (as always) to pointers to the zeroth elements of the arrays (of type struct record * ), and the assignment would be invalid because the left operand is not an lvalue.