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What is the difference between an array element and a variable?
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∙ 15y ago
Array elements are all members of the same variable, indexed in a logical manner. variables are distinct objects which must be referred to distinctly. The main functional difference is that a program can iterate over an array without the programmer knowing the original size of the array or explicitly which member to access.
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∙ 15y ago
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Why is an array called a derived data type?
An array is not a derived data type at all. In order to be derived there has to be a base class and an array has no base class. Here is the basic declaration of the std::array template class from the <array> header file: template<class _Ty, size_t _Size> class array { // fixed size array of values // ... }; A vector, on the other hand, is derived (from the <vector> header file): template<class _Ty, class _Alloc = allocator<_Ty>> class vector : public _Vector_alloc<!is_empty<_Alloc>::value, _Vec_base_types<_Ty, _Alloc>> { // varying size array of values // ... };
What does raid stand for?
"Redundant Array of Independent Disks"or you can also say"Redundant Array of Inexpensive Disks"RAID means you have your computers Hard drives linked to work in sync with each other,this could be used to back up data instantly or used to make your Hard drives all work as one big storage device.If you had two 500GB drives and put them in RAID you could make them act as one 1TB drive,the data would be split between the two drives.Redunant Array of Independant Disks.
Dope vector method for one dimentional array?
Dope Vector Method is use for one dimensional array and also two-dimensional array for one dimensional array we use MA(i)=sa+(i-1)*w MA is Memory Address Sa = Start Address i is subscript W for integer w=2 float=4 char=1 for two dimensional array MA(i,j)=SA{n(i-1)+(j-1)}*W
What computer device uses a spinning color wheel in communication with a micropocessor array of mirrors?
DLP projectors are pieces of computer hardware which use the color wheel and microprocessor array you referenced.
Suggestions for mini project in data structures using c?
1. Define a structure? A. A structure is a set of variables positioned under one name, offering a suitable means of relevant information together. Declaration of structure creates a template which can be used to produce structure objects that are called as its instances. The variables which form the structure are called as members, also referred as fields or elements. 2. Define a pointer? A. A pointer is nothing but a reference to some memory location. As a computer has billions or may be even trillions of cells, every cell can be filled with some data. With the help of pointers, one can know and access the value of its memory cell and its location. 3. What are the advantages of a pointer? A. Dynamic Memory Allocation, Passing structures and array to functions, creating data structures like linked lists, trees and so on, and passing addresses to functions. 4. Define static variable? A. A special variable which is stored in the data segment not like the default auto variable that is stored in stack, is called static variable. It can be initialized through using keyword static before variable name. 5. How are structure passing and returning implemented? A. When you pass structures as arguments to functions, the whole structure is usually pushed on the stack, through as several words as are needed. To avoid this overhead, programmers usually opt to use pointers to structures instead. Some compilers simply pass a pointer to the structure, even though they have to produce a local copy to save pass-by-value semantics. Structures are usually returned from functions in a position pointed to by an additional, compiler-supplied hidden argument to the function. Few older compilers used to use unique, static locations for structure returns, though this made structure-valued functions non-reentrant that ANSI C disapproves. 6. Why can't we compare structures? A. We do not have one or fine way for a compiler to apply structure evaluation that is constant with lower level flavor of C. A plain byte-by-bye comparison could be found on random bits available in unused 'holes' in the structure; such filling is used to maintain the arrangement of following fields accurate. A field-by-field assessment may require improper amounts of recurring code for larger structures. 7. Why doesn't struct x { … };x thestruct; work? A. C is not similar to C++. Typedef names are not automatically produced for structure tags 8. Why doesn't this code: a[i] = i++; work? A. The subexpression i++ creates a side effect. It changes i's value which directs to undefined behavior as i as well is referenced somewhere else in the same expression 9. Can we initialize unions? A. ANSI C permits an initializer for the foremost member of a union. We do not have any standard method of initializing other members (there is no way even under a pre-ANSI compiler to initialize a unionl) 10. Can main () be called recursively? A. Yes, any function that has main() could be called recurrently. 11. Are the variables argc and argv are always local to main? A. Yes, argc and argv are local to main 12. What would be the similar pointer expression for referring the equivalent element as a[p][q][r][s]? A. *( * ( * ( * (a+p) + q ) + r ) + s) 13. Are the expressions *ptr ++ and ++ *ptr same? A. No. *ptr++ increments pointer, not the value pointed by it. Where as ++*ptr increments the value being pointed to by ptr. 14. What are the benefits of using array of pointers to string instead of an array of strings? A. (i) Effective usage of memory (ii) Simpler to swap the strings through moving their pointers when sorting 15. Discuss on pointer arithmetic? A. (i) Assigning pointers to the similar kind of pointers (ii) Subtracting or adding a pointer and an integer (iii) comparing and subtracting two pointers (iv) Decrementing or incrementing the pointer that are pointing to the elements of an array while a pointer to an integer is added by one, the address is added by two. The Compiler does this automatically. Assiging value 0 to the pointer variable and comparing it with the pointer. Pointer consisting 0 points to nothing at all 16. What is the invalid pointer arithmetic? A. (i) Adding, dividing and multiplying two pointers (ii) Adding double or float to pointer (iii) Masking or shifting pointer (iv) Assigning a pointer of one type to another type of pointer. 17. Is the allocated space within a function automatically deallocated when the function returns? A. None of the pointers are similar to that of what they actually point to. Local variables like local pointer variables in a function are automatically deallocated if function returns. However, coming to a local pointer variable, deallocation is nothing but the pointer being deallocated and not blocking of memory allocated to it. Memory that is allocated dynamically always continues till the program terminates or allocation is freed. 18. What are the pointer declarations used in C? A. (i) Pointers to an array (ii) Array of pointers (iii) Pointer to a data type (iv) Pointer to a pointer (v) Function returning a pointer 19. Can we use any name in place of argv and argc as command line arguments? A. Yes. We can certainly use any user defined name instead of argc and argv. 20. Difference between an array of pointers and a pointer to an array? A. Array of pointers (i) Declaration - data type *array_name[size] (ii) Size indicates size of the row (iii) The space for columns may be dynamically allocated Pointer of Arrays (i) Declaration - data_type (*array_name)[size] (ii) Size indicates size of the column 21. Difference between an array name and a pointer variable? A. A pointer variable is a variable while an array name is not a variable but is a fixed address. Unlike a pointer variable, array name cannot be initialized. An array name being a constant value, - and ++ operators can not be applied to it. 22. What is the purpose of rewind()? A. The rewind() function is used to get the file pointer to the starting of the file. Rewind (fp); Fp is a file pointer. And we can get similar effect through feek(fp,0,0); 23. What is the purpose of ftell? A. The ftell() function is used to get the current file referred by the file pointer. ftell(fp); returns a long integer value referring the current location of the file pointed by the file pointer fp. If any error occurs, it will return -1. 24. What is a random access file? A. A file can be accessed at random through function fseek(), fseek(fp,position,origin); file pointer number file pointer fp positions number of bytes offset origin from 0, 1 or 2 denoting the starting, current or end position of the file respectively. 25. How is fopen()used? A. The fopen() function return a file pointer. So a file pointer is declared and is assigned as FILE *fp; fp=fopen(filename,mode); 26. How is a file closed? A. A file is closed using fclose() function 27. What is a file pointer? A. The pointer to a FILE data type is known as a file pointer or a stream pointer. This pointer points to the block of information of the stream/file that had just been accessed. 28. What is a stream? A. A stream is nothing but source of destination of data or simply data that is associated with a hard disk or other input/output device. The source stream that offers data to a program is known as input stream and the source stream that receives the result from the program is known as output stream. 29. What is meant by file opening? A. The process of connecting a program to a file is known as file opening. It needs I/O stream creation in advance to writing or reading the data. 30. What exactly is a file? A. A file is an area of storage in auxiliary storage devices or in hard disks. It includes information in bytes. 31. What are the types of files? A. Files are of two types 1-high level files (stream oriented files) - These are accessed through library functions 2-low level files (system oriented files) - These are accessed through system calls 32. What is the difference between the functions memmove() and memcpy()? A. The arguments of memmove() can overlie in memory, while the arguments of memcpy() cannot 33. What do the functions atoi(), itoa() and gcvt() do? A. atoi() is a macro that converts integer to character. itoa() It converts an integer to string gcvt() It converts a floating point number to string 34. How would you use the functions randomize() and random()? A. Randomize() initiates random number generation with a random value. Random() generates random number between 0 and n-1 35. What are the two forms of #include directive? A. 1. #include"filename" 2. #include 36. What are the facilities provided by preprocessor? A. File inclusion, substitution facility and conditional compilation 37. What is a preprocessor? What are the advantages of preprocessor? A. Preprocessor practices the source code program before it is sent through the compiler. (i) It includes the readability of a program (ii) It helps in easier modification (iii) It facilitates writing convenient programs (iv) It helps in easier debugging (v) It helps in testing a portion of program (vi) It enables implementing comprehensive program 38. Define bit fields? Point out their uses in Structure declaration? A. A bit field is a group of adjoining bits in a one execution based on storage unit which we call as a "word". Usually, the field definition's syntax and access is based on a structure. Struct { unsigned int k :1; unsigned int l :1; unsigned int m :1; }flags; The number that is preceeding the colon indicates the field width. And flag is a variable that includes 3 bit fields. 39. What is the maximum combined length of command line arguments including the space between adjacent arguments? A. It depends on the operating system 40. Compose a program to swap two variables without the help of third variable. A. a^=b; b^=a; a^=b; In the above program, the numbers are converted into binary numbers and then xor operator is executed. 41. What is pre-increment and post-increment? A. ++num (pre-increment) increases value of num before it is used in the expression, where num++ (post-increment) increases the num after its value is used. 42. Difference between logical vs syntax errors? A. Logical error: It occurs by a wrong algorithm or a mistyped statement in such a way that it does not violate the syntax, and these are difficult to find. Syntax error: It involves syntax validation, and compiler prints diagnostic message. Ex: a=b 43. What are C identifiers? A. C identifiers are the names given to different programming elements like arrays, functions and variables. It is usually a combination of a letter, a digit and an underscore. It should start with a letter, and backspace is not allowed. 44. What are C tokens? A. There are 6 classes of C tokens - keywords, constants, identifier, operators, string literals and other separators. 45. What do the 'c' and 'v' in argc and argv stand for? A. The c in argument count, argc stands for the number of the command line argument that the program is invoked with. And v in argument vector, argv is a pointer to an array of the character string that contains the argument. 46. Difference between array and pointer? A. Array: (i) Arrays allocate space, automatically (ii) They can not be reassigned (iii) They can not be resized (iv) sizeof (arrayname) returns the number of bytes occupied by the array. Pointer: (i) Assigned explicitly to point an allocated space. (ii) It can be reassigned (iii) It can be resized using realloc() function (iv) sizeof (p) gives the number of bytes used to store the pointer variable p. 47. Compose a program using Command Line Arguments? A. #include void main(int argc,char *argv[]) { int i; clrscr(); for(i=0;i printf("\n%d",argv[i]); } 48. Write a program which employs Recursion? A. int fact(int n) { return n > 1 ? n * fact(n - 1) : 1; } 49. How can we read/write Structures from/to data files? A. To compose a structure fwrite() can be used as Fwrite(&e, sizeof(e),1,fp); Here, e is a structure variable. A consequent fread() invocation will be able to read the structure back from file. Calling function fwrite() will write out sizeof(e) byte from the address & e. Data files that are written as memory images with function fwrite(), but will not be portable, especially if they include floating point fields or pointers. It is because structures' memory layout is compiler and machine dependent. Hence, structures written as memory are not need to be read back by programs running on other machine, also this is an important factor if the data files that you are writing will ever be exchanged between machines. 50. Can a Structure contain a Pointer to itself? A. Yes such structures are called self-referential structures. Other Questions What is the similarity between a Structure, Union and enumeration? How are Structure passing and returning implemented by the complier? What is the difference between an enumeration and a set of pre-processor # defines? Is it possible to have more than one main() function in a C program? Difference between formal argument and actual argument? What are built in functions? What is an argument? What is a function? What modular programming? Why is it necessary to give the size of an array in an array declaration? Is it possible to have negative index in an array? Difference between linker and linkage? What is an array of pointers? What is pointer to a pointer? What is the purpose of realloc? What is dynamic memory allocation? What is static memory allocation? How pointer variables are initialized? Are the expressions arr and &arr same for an array of integers? What is generic pointer in C? What does the error 'Null Pointer Assignment' means and what causes this error? Are pointers integer? What is a NULL Pointer? Whether it is same as an uninitialized pointer? In C, why is the void pointer useful? When would you use it? What is near pointer? What is a normalized pointer, how do we normalize a pointer? What is a huge pointer? What is a far pointer? Where do we use it? What is the difference between Strings and Arrays? What the advantages of using Unions? What is storage class? What are the different storage classes in C? Differentiate between a for loop and a while loop? What are it uses? What is recursion? Difference between strdup and strcpy? Out of fgets() and gets() which function is safe to use and why? Can we specify variable field width in a scanf() What is the use of typedef? What are register variables? What are the advantages Describe about storage allocation and scope of
What is an individual storage location in an array?
swag variable
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 array What is difference between array and simple variable?
An array stores several values - for example, several numbers - using a single variable name. The programmer can access the individual values with a subscript, for example, myArray[0], myArray[5]. The subscript can also be a variable, for example, myArray[i], making it easy to write a loop that processes all the elements of an array, or some of them, one after another.
How can you search an array element in a file?
Logic to search element in array Input size and elements in array from user. ... Input number to search from user in some variable say toSearch . Define a flag variable as found = 0 . ... Run loop from 0 to size . ... Inside loop check if current array element is equal to searched number or not. To learn more about data science please visit- Learnbay.co
How do you use subscripts with an array?
An array is a list of several related elements. You use the subscript to specify which element you want to access. For example, in Java you might have an array called myArray, with 10 elements (numbered from 0 to 9); myArray[3] would access the fourth element in the array. A variable may be used instead of a constant.
What is the difference between subscript and subscripted variable in c plus plus?
Subscripts are used to identify the elements in an array, where the first element has subscript 0. Thus an array of n elements has subscripts in the range 0 to n-1. Each element may itself be an array, thus allowing multi-dimensional arrays. The subscript may be a constant or a variable. However, when declaring a static array, the subscript must be a constant. Constants include literal constants as well as named constants. A subscripted variable is simply an array or a datatype that can be divided into an array. For instance, a 32-bit int can be treated just as if it were an array of two 16-bit shorts or four 1-byte chars. Thus in the 32-bit int array, int i[10], i is a subscripted variable where i[0] is the first integer and i[9] is the last. If we then say char*c=&i, c would allow us to treat i as if it were a subscripted variable with 40 char elements (c[0] to c[39]).
What is difference between key and index in php arrays?
A key is the name of a variable in an array ($array["key"]) and the index is the position it's at ($array = ["key" => 0], the index would be 0). Keys and indices are the same if the array is not associative though ($array = [true], the key holding the value true is named 0 and is at index 0).
How do you calculate array elements value?
You don't need to calculate an array element's value. An array element is a variable and like any variable you can access its value directly. There is nothing to calculate: int a[5] {0, 2, 4, 6, 8}; int x = a[2]; // x=4 The only thing that really needs calculating is the index of the element you wish to access. If you know the index, then there's nothing to calculate.
What is the difference between array element and variable?
• Array is the set of an multiple values where as variable can store single value at a time.• The difference between the definition of array and ordinary variable is the, array is always declared, initialized, and accessed using subscript whereas ordinary variable do not have any subscript.• The syntax for ordinary variable definition is data_type v1, v2, ….;• And the syntax for array variable is data_type v1[N1],v2[N2],…; where v1,v2 are name of variable and N1, N2 are the integer constants indicating the maximum size of array.
Index of an element in array?
An array is a group of related elements, with a common variable name. The index is a number that indicates the position of an element within an array: the 1st. element, the 2nd. element, etc. (many languages start counting at zero).
How do you access 2D array elements by using single variable?
int main() { int array[3][3]; int i; for(i=0; i <9;i++) { printf("the element is %d\n", array[i/3][i%3]); } return 0; }
What is the relationship between the value of the subscript and the value of the array element in c?
You can access the array-element via index (or subscript), but it is not possible the other way around.
