Ngăn xếp (stack)

1stack = []2
3# Push three values onto the top4for value in [3, 7, 5]:5    stack.append(value)6    print(f"push {value} -> {stack}")7
8# Pop them back off: last in, first out9while stack:10    value = stack.pop()11    print(f"pop  {value} -> {stack}")12
13print("empty:", len(stack) == 0)

1const stack = [];2
3// Push three values onto the top4for (const value of [3, 7, 5]) {5    stack.push(value);6    console.log(`push ${value} ->`, stack);7}8
9// Pop them back off: last in, first out10while (stack.length > 0) {11    const value = stack.pop();12    console.log(`pop  ${value} ->`, stack);13}14
15console.log('empty:', stack.length === 0);

1import java.util.ArrayDeque;2import java.util.Deque;3
4public class Main {5    public static void main(String[] args) {6        Deque<Integer> stack = new ArrayDeque<>();7
8        // Push three values onto the top9        for (int value : new int[] {3, 7, 5}) {10            stack.push(value);11            System.out.println("push " + value + " -> " + stack);12        }13
14        // Pop them back off: last in, first out15        while (!stack.isEmpty()) {16            int value = stack.pop();17            System.out.println("pop  " + value + " -> " + stack);18        }19
20        System.out.println("empty: " + stack.isEmpty());21    }22}

1#include <iostream>2#include <stack>3
4int main() {5    std::stack<int> stack;6
7    // Push three values onto the top8    for (int value : {3, 7, 5}) {9        stack.push(value);10        std::cout << "push " << value << " -> size " << stack.size() << "\n";11    }12
13    // Pop them back off: last in, first out14    while (!stack.empty()) {15        int value = stack.top();16        stack.pop();17        std::cout << "pop  " << value << " -> size " << stack.size() << "\n";18    }19
20    std::cout << "empty: " << std::boolalpha << stack.empty() << "\n";21    return 0;22}

1#include <stdio.h>2
3#define CAP 164
5int stack[CAP];6int top = 0; /* index of the next free slot */7
8int main(void) {9    int values[3] = {3, 7, 5};10
11    /* Push three values onto the top */12    for (int i = 0; i < 3; i++) {13        stack[top++] = values[i];14        printf("push %d -> size %d\n", values[i], top);15    }16
17    /* Pop them back off: last in, first out */18    while (top > 0) {19        int value = stack[--top];20        printf("pop  %d -> size %d\n", value, top);21    }22
23    printf("empty: %d\n", top == 0);24    return 0;25}