关于编程语言：什么是指针？

What is a Pointer?

本问题已经有最佳答案，请猛点这里访问。

参见：理解指针

在许多C语言中，以及一些旧的语言，如Fortran，都可以使用指针。

作为一个真正用BASIC、JavaScript和ActionScript编程的人，你能向我解释什么是指针，什么是最有用的吗？

谢谢！

这篇维基百科文章将为您提供关于指针是什么的详细信息：

In computer science, a pointer is a programming language data type whose value refers directly to (or"points to") another value stored elsewhere in the computer memory using its address. Obtaining or requesting the value to which a pointer refers is called dereferencing the pointer. A pointer is a simple implementation of the general reference data type (although it is quite different from the facility referred to as a reference in C++). Pointers to data improve performance for repetitive operations such as traversing string and tree structures, and pointers to functions are used for binding methods in Object-oriented programming and run-time linking to dynamic link libraries (DLLs).

指针是包含另一个变量地址的变量。这允许您间接引用另一个变量。例如，在c中：

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// x is an integer variable
int x = 5;
// xpointer is a variable that references (points to) integer variables
int *xpointer;
// We store the address (& operator) of x into xpointer.
xpointer = &x;
// We use the dereferencing operator (*) to say that we want to work with
// the variable that xpointer references
*xpointer = 7;
if (5 == x) {
// Not true
} else if (7 == x) {
// True since we used xpointer to modify x
}