Elysian Shadows

Code: Select all

struct element {
	struct element *next;
	int value;
};
 
struct element *head = NULL;
 
void insert(struct element *item) {
	struct element **p;
	for(p = &head; *p != NULL; p = &(*p)->next) {
		if(item->value <= (*p)->value) {
			break;
		}
	}
	item->next = *p;
	*p = item;
}


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Pointers are directly supported without restrictions in languages such as C, C++, Pascal and most assembly languages. They are primarily used for constructing references, which in turn are fundamental to constructing nearly all data structures, as well as in passing data between different parts of a program.

In functional programming languages that rely heavily on lists, pointers and references are managed abstractly by the language using internal constructs like cons.

When dealing with arrays, the critical lookup operation typically involves a stage called address calculation which involves constructing a pointer to the desired data element in the array. In other data structures, such as linked lists, pointers are used as references to explicitly tie one piece of the structure to another.

Pointers are used to pass parameters by reference. This is useful if we want a function's modifications to a parameter to be visible to the function's caller. This is also useful for returning multiple values from a function.