stack pointer definition

例句：

1. 1.The stack pointer is used to indicate the current position in a stack.
   堆栈指针用于指示堆栈中的当前位置。
2. 2. The stack pointer is used to manage memory allocation and deallocation.
   堆栈指针用于管理内存分配和释放。
3. 3.The stack pointer is used to determine the top of the stack.
   堆栈指针用于确定堆栈的顶部。