How to make a 2D char array completely empty?

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I am creating a 2D array using malloc and when I iterate through the array there are characters and symbols that I do not want in there. Shouldn't the array be completely empty?

I have tried to assign the null character to the beginning of each row but that doesn't change anything.

    char **structure;
    structure = malloc(sizeof *structure * 2);
    if (structure) {
        for (size_t i = 0; i < 2; i++) {
            structure[i] = malloc(sizeof *structure[i] * 20);
            structure[i][0] = '\0';
    for (int i = 0; i <= 2; i++) {
        for (int j = 0; j < 20; j++) {
            printf("%c ", structure[i][j]);

I expected the output to just be blank spaces but this is what appeared:

Z Ñ             P  Ñ             l   L O
Z Ñ               P  Ñ             N U M B

You should use the calloc function; this is what I often use. It does the same work as malloc() but it initializes all allocated bits with 0.

calloc documentation

How to empty a 2d char array in C?, you are just modifying the first element of each sub-array Have another variable like j, then create an inner for loop with it from 0 to columnSize - 1. You can empty a char * by making it's first character the null plug. ( By Dan Gookin . Just as you can declare an empty, or uninitialized, float or int array, you can create an empty char array with C programing. You must be precise, however: The array’s size must be 1 greater than the maximum length of the string to account for that NULL character.

As you are accessing each character you must clear all position explicitly to get your desired output.

char **structure;
structure = (char**)malloc( (sizeof *structure) * 2 );
if (structure)
    for(size_t i = 0; i < 2; i++){
        // structure[i];
    structure[i] =(char *) malloc( sizeof *structure[i] * 20 );
    for(int j=0; j<20; j++)
        structure[i][j] = '\0';

for(int i = 0; i < 2; i++){ //you can not access position i==2
        for(int j = 0; j < 20; j++)
            printf("%c ", structure[i][j]);


You can also use printf("%s", structure[i]) to make it work with your current code. it will work because you have made first position of both strings NULL('\0').So printf function will terminate for both character arrays without printing anything. But remember, other position than the first one of both arrays will contain garbage value.

help with simple initialize 2-d char array, Anyway, I want to initialize a 2d character array of 8x8 in size. Initially, I want to initialize all slots to blank space. so is this it Code: [View]. Benchmark, char array. Character arrays can be used to store character data such as letters or numbers. Here we append characters one-by-one to an array using the char data type. Note: Remember that chars in the C# language are 2 bytes. So for each char, 2 bytes are copied on the stack. Version 1: This version uses a char array. We assign each

When you are allocating memory the data inside the memory is undefined. the malloc function just giving you the memory. if you want the memory to be initialized to 0 you can always use the standard calloc function. If you want to initialize it after allocation you can always use the memset function. in your case

memset(structure, 0,  (sizeof *structure) * 2)

How to declare and Initialize two dimensional Array in Java with , Character array is a bit tricky because if you print 0 as a character it will print a null character and that's why I have used its integer value by casting to int. We can say that a 2d array is an array of array. A multidimensional array is mostly used to store a table-like structure. In today’s topic, we are going to see this 2-dimensional array. 2 dimensional Array has two pairs of square brackets. first one for row and the second one for the column.

You are not really allocating a 2D array of char, but an array of 2 pointers to arrays of 20 char. It is much simpler to allocate a true 2D array:

// allocate a 2D array and initialize it to null bytes
char (*structure)[20] = calloc(sizeof(*structure), 2);
for (int i = 0; i < 2; i++) {
    for (int j = 0; j < 20; j++) {
        printf("%02X ", structure[i][j]);


00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 

Create empty array of specified class - MATLAB empty, This example shows how to create an empty character array using the default dimensions, 0-by-0. A = char.empty. Use ClassName.empty to create a 0-by-0 array of the ClassName class. Use ClassName.empty(m,0) to create an m-by-0 array of the ClassName class. This function is useful for creating empty arrays of data types that do not have a special syntax for creating empty arrays, such as [] for double arrays.

Two Dimensional Array in Java, Two dimensional array in java, Java 2d array, java multidimensional array, Well, it's absolutely fine in java. public class MultidimensionalArrayExample { public static void main(String[] args) { // creating and initializing two dimensional array with If not can you tell me how to provide hard coded value to 2d char array. You can initialize it the way your instructor suggested as you declare the array: char mychararray[35] = ""; It will set the array to an empty string. If you want to make it an empty string later, then you can just do. mychararray[0] = '\0'; If you want to make it an array consisting of 34 spaces (35th character being null terminator), then

java create 2d char array Code Example, Get code examples like "java create 2d char array" instantly right from your google public void sendData(byte[] data, InetAddress ipAddress, int port) throws how to destroy a gameobject permanently unity when player go through it 2d� The type of both the variables is a pointer to char or (char*), so you can pass either of them to a function whose formal argument accepts an array of characters or a character pointer. Here are the differences: arr is an array of 12 characters. When compiler sees the statement:

Convert to cell array of character vectors - MATLAB cellstr, This MATLAB function converts A to a cell array of character vectors. You can create string arrays to contain multiple pieces of text. If any element of A is a missing string (displayed as <missing> ), then cellstr assigns an empty character array to the corresponding cell of the This function fully supports distributed arrays. Java Char Array Size or Length. This was actually shown in previous example, but below is a sample way if we want to know the length of an existing char array. char[] thisIsACharArray = {'a', 'z', 'c', 'm', 'x'}; System.out.println(thisIsACharArray.length); This will output 5 as this is the number of items in the array. 5 Java Char Array Sorting

  • Please define "empty". That needs a definition. Are spaces "empty" elements of the array? Are null charactes empty elements of the array? Or does some int tells you how many elements are in use?
  • "I expected the output to just be blank spaces" Why?
  • Note: in the second loop the limit i <= 2; is incorrect and breaks the array bounds. It should be i < 2;
  • There is no such thing as an empty array or an empty char. You need to figure out which values you want to use.
  • Other people have covered the main point, but be aware that what you've got above is not a 2D array - it's an array of pointers, a very different construct with very different use cases and advantages (mainly, it can be "jagged"). A 2D array in C is an array-of-arrays - can still be dynamically allocated, but not like this.
  • Your diagnotics and correction are valid. But your assumption about printf("%c", 0) is not. printf will output a null byte, and this null byte would appear in the file should the standard output be redirected to a file. The terminal may or may not show null bytes. For illustration purposes, structure[i][j] should be set to a visible character.
  • A better example would be memset(structure[i], 0, 20); or possibly memset(structure[i], 0, (sizeof(*structure[i]) * 20);. The pointer array hardly need initializing.