C ++程序使用两个队列实现堆栈
叠放
实现为LIFO的堆栈，其中插入和删除从同一末端开始。输入的最后一个元素首先被删除。
堆栈操作是-
push（int数据）-在顶部插入
INTpop() -删除从顶部
队列
被实现为FIFO的队列，其中插入是在一端（后部）完成，而删除是在另一端（前部）完成。输入的第一个元素首先被删除。
队列操作是-
EnQueue（int数据）-在后端插入
INTDeQueue()-删除从前端
这是一个使用两个队列实现堆栈的C++程序
演算法
Begin
function enqueue1 to insert item a at qu1:
Set, np1 = new qu1
np1->d1 = a
np1->n1 = NULL
if (f1 == NULL)
Then set
r1 = np1
r1->n1 = NULL
f1 = r1
else
r1->n1 = np1
r1 = np1
r1->n1 = NULL
End
Begin
function dequeue1 to delete item from qu1.
if queue is null
Print no elements present in queue.
Else
q1 = f1
f1 = f1->n1
a = q1->d1
delete(q1)
return a
End
Begin
function enqueue2 to insert item a at qu2.
np2 = new qu2;
np2->d2 = a;
np2->n2 = NULL;
if queue is null
Set r2 = np2
r2->n2 = NULL
f2 = r2
Else
Set r2->n2 = np2
r2 = np2
r2->n2 = NULL
End
Begin
function dequeue2 to delete item from qu2:
if queue is null
Print no elements present in queue.
Else
q2 = f2
f2 = f2->n2
a = q2->d2
delete(q2)
return a
End范例程式码
#include<iostream>
using namespace std;
struct qu1// queue1 declaration {
qu1 *n1;
int d1;
}*f1 = NULL, *r1 = NULL, *q1 = NULL, *p1 = NULL, *np1 = NULL;
struct qu2// queue2 declaration {
qu2 *n2;
int d2;
}*f2 = NULL, *r2 = NULL, *q2 = NULL, *p2 = NULL, *np2 = NULL;
void enqueue1(int a) {
np1 = new qu1;
np1->d1 = a;
np1->n1 = NULL;
if (f1 == NULL) {
r1 = np1;
r1->n1 = NULL;
f1 = r1;
} else {
r1->n1 = np1;
r1 = np1;
r1->n1 = NULL;
}
}
int dequeue1() {
int a;
if (f1 == NULL) {
cout<<"no elements present in queue\n";
} else {
q1 = f1;
f1 = f1->n1;
a = q1->d1;
delete(q1);
return a;
}
}
void enqueue2(int a) {
np2 = new qu2;
np2->d2 = a;
np2->n2 = NULL;
if (f2 == NULL) {
r2 = np2;
r2->n2 = NULL;
f2 = r2;
} else {
r2->n2 = np2;
r2 = np2;
r2->n2 = NULL;
}
}
int dequeue2() {
int a;
if (f2 == NULL) {
cout<<"no elements present in queue\n";
} else {
q2 = f2;
f2 = f2->n2;
a = q2->d2;
delete(q2);
return a;
}
}
int main() {
int n, a, i = 0;
cout<<"Enter the number of elements to be entered into stack\n";
cin>>n;
while (i < n) {
cout<<"enter the element to be entered\n";
cin>>a;
enqueue1(a);
i++;
}
cout<<"\n\nElements popped\n\n";
while (f1 != NULL || f2 != NULL)// if both queues are not null {
if (f2 == NULL)// if queue 2 is null {
while (f1->n1 != NULL) {
enqueue2(dequeue1());
}
cout<<dequeue1()<<endl;
} else if (f1 == NULL)//if queue 1 is null {
while (f2->n2 != NULL) {
enqueue1(dequeue2());
}
cout<<dequeue2()<<endl;
}
}
}输出结果
Enter the number of elements to be entered into stack 5 enter the element to be entered 1 enter the element to be entered 2 enter the element to be entered 3 enter the element to be entered 4 enter the element to be entered 5 Elements popped 5 4 3 2 1