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Array subscript values are always integer...!!why?

6th Dec 2017, 10:05 AM
Thriveni
Thriveni - avatar
1 Réponse
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Array indexes are always integers, because at the lowest level, arrays are contiguous blocks of memory, and the array is simply represented by a pointer to its first element. The program has to perform numeric addition to this pointer to retrieve the successive element from the allocated memory. Eg : When you do : int a[5]; a[2]=3; printf("%d",a[2]); or int[] a=new int[5]; a[2]=3; System.out.print(a[2]); The a[2] is translated into *(a+2), where a is the first element. Thus, if the index is non-integer, it cannot be used to retrieve from memory. But if you wish to retrieve something like this: a['c']; // c is the 3rd element, not the 99th you may use Map, which maps the element with a unique key, which can then be used to retrieve an element. The implementation at the lowest level, however still uses integers to retrieve the data.
6th Dec 2017, 10:43 AM
Solo Wanderer 4315
Solo Wanderer 4315 - avatar