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Depends on the programming language, some languages may have already initialize an array with null (or the default value of the type), some of them require explicitly assignments by stepping through each element of that array, and assigning them with null. (imperative languages)
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What is the difference between an array shift and unsetting a variable in PHP?
By shifting the values in an array, you are moving a key's value to the previous key. The very first key's value is obliterated. By shifting all values in the array, all keys will have a value of NULL. Unsetting a variable is entirely different -- performing a variable unsetting causes the variable to have a value of NULL, as if it was never set.
What is NULL array in C Language?
There is no "NULL array" as such, you may take a pointer to an array and set it to NULL (binary 0) e.g. int* foo; // Declare a pointer foo = malloc( 40 * sizeof(int)); //Allocate an array of 40 integers pointed to by "foo" foo = NULL; //Set the pointer to NULL, if you're using a garbage collector this should trigger an automatic free() of the memory allocated to the array. If you are NOT using a garbage collector (which is more common in C) this line is a memory leak.
How can i check a null at the end of an character array in java?
A character array, by nature, is a primitive-type data array. It can't contain a null value. You cannot cast a char as a null. char[] charArray = {'1','2','s',null}; //this doesn't compile. However, if you have an array of Character objects, then it's possible. Character[] charArray = {'1','2','s',null}; //this DOES compile A proposed algorithm is to initialize a test boolean as false, then use a for loop to iterate through the array. Set the flag to true (and break the loop) based upon whether one of the objects you run into is null. What you do from there is up to what the rest of your code says.
What is the difference between null array and an empty array?
There is no null array as such. However, a pointer to an array may be nullified (pointing to zero) before memory is allocated to it, or after that memory is released. But the same is true of any pointer. That is, the pointer is NULL, not what it previously pointed to. An empty array usually refers to a dynamic array for which no memory has yet been allocated (in other words, a null pointer). However, the term can also apply to static arrays or dynamic arrays that have been allocated memory, where every element is initialised with a value that has no significance. For instance, an array of natural numbers (positive integers greater than 0) might be initialised with the value 0 (a non-natural number) in every element to indicate that the array is empty. By contrast, individual elements could be set to zero to indicate which elements are available (an empty element as opposed to an empty array).
What is mean by Extra key inserted at the end of Array?
It means the array has a sentinel to mark the end of the array. Any elements that follow the sentinel element are deemed invalid. Sentinels are usually denoted with a special value that is not used by any of the elements that precede it. Null-terminated strings are an example, where the NULL character (ASCII code 0) marks the end of a character array.
Delete an element from an options array?
Set it to null
What is the difference between an array shift and unsetting a variable in PHP?
By shifting the values in an array, you are moving a key's value to the previous key. The very first key's value is obliterated. By shifting all values in the array, all keys will have a value of NULL. Unsetting a variable is entirely different -- performing a variable unsetting causes the variable to have a value of NULL, as if it was never set.
What is NULL array in C Language?
There is no "NULL array" as such, you may take a pointer to an array and set it to NULL (binary 0) e.g. int* foo; // Declare a pointer foo = malloc( 40 * sizeof(int)); //Allocate an array of 40 integers pointed to by "foo" foo = NULL; //Set the pointer to NULL, if you're using a garbage collector this should trigger an automatic free() of the memory allocated to the array. If you are NOT using a garbage collector (which is more common in C) this line is a memory leak.
How can i check a null at the end of an character array in java?
A character array, by nature, is a primitive-type data array. It can't contain a null value. You cannot cast a char as a null. char[] charArray = {'1','2','s',null}; //this doesn't compile. However, if you have an array of Character objects, then it's possible. Character[] charArray = {'1','2','s',null}; //this DOES compile A proposed algorithm is to initialize a test boolean as false, then use a for loop to iterate through the array. Set the flag to true (and break the loop) based upon whether one of the objects you run into is null. What you do from there is up to what the rest of your code says.
What is the difference between null array and an empty array?
There is no null array as such. However, a pointer to an array may be nullified (pointing to zero) before memory is allocated to it, or after that memory is released. But the same is true of any pointer. That is, the pointer is NULL, not what it previously pointed to. An empty array usually refers to a dynamic array for which no memory has yet been allocated (in other words, a null pointer). However, the term can also apply to static arrays or dynamic arrays that have been allocated memory, where every element is initialised with a value that has no significance. For instance, an array of natural numbers (positive integers greater than 0) might be initialised with the value 0 (a non-natural number) in every element to indicate that the array is empty. By contrast, individual elements could be set to zero to indicate which elements are available (an empty element as opposed to an empty array).
What is the difference between array and string of array?
When we declare an array of characters it has to be terminated by the NULL , but termination by NULL in case of string is automatic.
How you can find out the number of elements and free elements in a pointer array?
You can find the number of elements and free elements in a pointer array by iterating through the array and counting the number of elements that are null versus the number that are non-null. Of course, this technique's success depends on proper initialization of each element, i.e. when first created or when deleted, it must be set to null.
What is the subset of null set?
The null set. Every set is a subset of itself and so the null set is a subset of the null set.
Is it right saying that the null set is not equal to the set containing null set as its only element?
A null set is a set with nothing in it. A set containing a null set is still containing a "null set". Therefore it is right to say that the null set is not the same as a set containing only the null set.
What is mean by Extra key inserted at the end of Array?
It means the array has a sentinel to mark the end of the array. Any elements that follow the sentinel element are deemed invalid. Sentinels are usually denoted with a special value that is not used by any of the elements that precede it. Null-terminated strings are an example, where the NULL character (ASCII code 0) marks the end of a character array.
What is difference between null value and not null value?
In databases: Null Value: Represents the absence of a value or an unknown value. It indicates that the data is missing or not applicable. Not Null Value: Indicates that a field contains a valid, defined value. It means the data is present and has been explicitly set.
Why is c string defined as an array?
Every programming language treats strings as arrays. A C string is defined as being a null-terminated array of characters. A C string that does not have a null-terminator is just an array of character values, but without a null-terminator the onus is upon the programmer to keep track of the array's length.
