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stack
Defined in header <ctl/stack.h>, CTL prefix stack, derived from deque.
#undef POD
#define T int
#include <ctl/stack.h>
stack_int a = stack_int_init ();
for (int i=0; i<rand(); i++)
stack_int_push (&a, i);
for (int i=0; i<rand(); i++)
stack_int_pop (&a); // ignores empty stack
stack_int_free(&a);
The stack is a container adapter that gives the programmer the functionality of a stack - specifically, a LIFO (last-in, first-out) data structure.
The header acts as a wrapper to the underlying container - only a specific set of functions is provided. The stack pushes the elements on the back of the underlying container and pops them from the front.
The function names are composed of the prefix stack_, the user-defined type
T and the method name. E.g stack_int
with #define T int
.
As opposed to vector, the elements of a stack are not stored contiguously: typical implementations use a sequence of individually allocated fixed-size arrays, with additional bookkeeping, which means indexed access to stack must perform two pointer dereferences, compared to vector's indexed access which performs only one.
The storage of a stack is automatically expanded and contracted as needed. Expansion of a stack is cheaper than the expansion of a vector because it does not involve copying of the existing elements to a new memory location. On the other hand, stacks typically have large minimal memory cost; a stack holding just one element has to allocate its full internal array (e.g. 8 times the object size on 64-bit libstdc++; 16 times the object size or 4096 bytes, whichever is larger, on 64-bit libc++).
T
value type
A
being stack_T
container type
B
being stack_T_node
node type (hidden)
I
being stack_T_it
iterator type (hidden)
init ()
constructs the stack.
free (A* self)
destructs the stack.
copy (A* self)
returns a copy of the container.
front (A* self)
access the first element
empty (A* self)
checks whether the container is empty
size (A* self)
returns the number of elements
max_size ()
returns the maximum possible number of elements
push (A* self, T value)
Push element before top
emplace (A* self, T values...)
Push elements before top. C++11, NYI
pop (A* self)
Removes the first element
swap (A* self, A* other)
Swaps the contents
equal (A* self, A* other, int T_equal(T*, T*))
Returns 0 or 1 if all elements are equal.