Search results
Results From The WOW.Com Content Network
To use column-major order in a row-major environment, or vice versa, for whatever reason, one workaround is to assign non-conventional roles to the indexes (using the first index for the column and the second index for the row), and another is to bypass language syntax by explicitly computing positions in a one-dimensional array.
Thus an element in row i and column j of an array A would be accessed by double indexing (A[i][j] in typical notation). This way of emulating multi-dimensional arrays allows the creation of jagged arrays, where each row may have a different size – or, in general, where the valid range of each index depends on the values of all preceding indices.
In computer science, a hash table is a data structure that implements an associative array, also called a dictionary or simply map; an associative array is an abstract data type that maps keys to values. [3] A hash table uses a hash function to compute an index, also called a hash code, into an array of buckets or slots, from which the desired ...
APL allows setting the index origin to 0 or 1 during runtime programmatically. [9] [10] Some recent languages, such as Lua and Visual Basic, have adopted the same convention for the same reason. Zero is the lowest unsigned integer value, one of the most fundamental types in programming and hardware design.
To further illustrate, imagine a relational model with two tables: a people table (which has a person_id and person_name column) and a friend table (with friend_id and person_id, which is a foreign key from the people table). In this case, searching for all of Jack's friends would result in the following SQL query.
Thus an element in row i and column j of an array A would be accessed by double indexing (A[i][j] in typical notation). This alternative structure allows jagged arrays, where each row may have a different size—or, in general, where the valid range of each index depends on the values of all preceding indices. It also saves one multiplication ...
In 493 AD, Victorius of Aquitaine wrote a 98-column multiplication table which gave (in Roman numerals) the product of every number from 2 to 50 times and the rows were "a list of numbers starting with one thousand, descending by hundreds to one hundred, then descending by tens to ten, then by ones to one, and then the fractions down to 1/144 ...
The second method is used when the number of elements in each row is the same and known at the time the program is written. The programmer declares the array to have, say, three columns by writing e.g. elementtype tablename[][3];. One then refers to a particular element of the array by writing tablename[first index][second index]. The compiler ...