﻿ C++ Sort a stack (using a dynamic array) elements

# C++ Stack Exercises: Sort a stack (using a dynamic array) elements

## C++ Stack: Exercise-21 with Solution

Write a C++ program that sorts the stack (using a dynamic array) elements.

Test Data:
Input the size of the stack: 5
Input some elements onto the stack:
Stack elements are: 4 7 5 3 1
After sorting the said stack elements:
Stack elements are: 1 3 4 5 7

Sample Solution:

C++ Code:

``````#include <iostream>

using namespace std;

// Class representing a Stack
class Stack {
public:
int top;        // Index of top element
int capacity;   // Maximum size of the stack
int* arra;      // Pointer to the array storing elements

// Constructor to initialize the stack with a given size
Stack(int size) {
arra = new int[size]; // Allocate memory for the stack array
top = -1;             // Initialize top index to -1 (empty stack)
capacity = size;      // Set the maximum capacity of the stack
}

// Function to push an element onto the stack
bool push(int x) {
if (isFull()) {
cout << "Stack is full" << endl; // Display overflow message if the stack is full
return false;
}
// Add element to array by incrementing top index
arra[++top] = x;
return true;
}

// Function to pop an element from the stack
int pop() {
if (isEmpty()) {
cout << "Stack underflow" << endl; // Display underflow message if the stack is empty
return 0;
}
// Return the top element and decrement the index of the top element
return arra[top--];
}

// Function to peek the top element of the stack without removing it
int peek() {
if (isEmpty()) {
cout << "Stack is empty" << endl; // Display message if the stack is empty
return 0;
}
// Return the top element without modifying the top index
return arra[top];
}

// Function to check if the stack is empty
bool isEmpty() {
// Stack is empty if top index is -1
return (top < 0);
}

// Function to check if the stack is full
bool isFull() {
// Stack is full if top index is equal to capacity - 1
return (top >= capacity - 1);
}

// Function to display the elements of the stack
void display() {
if (top < 0) {
cout << "Stack is empty" << endl; // Display message if the stack is empty
return;
}
cout << "\nStack elements are: ";
for (int i = top; i >= 0; i--)
cout << arra[i] << " "; // Display the elements of the stack
cout << endl;
}
};

// Function to sort the elements of a stack in descending order
void sort_stack(int* stackArray, int& top) {
int temp;
for (int i = 0; i <= top; i++) {
for (int j = i + 1; j <= top; j++) {
if (stackArray[j] > stackArray[i]) {
// Swap elements to arrange them in descending order
temp = stackArray[i];
stackArray[i] = stackArray[j];
stackArray[j] = temp;
}
}
}
}

int main() {
int size;
cout << "Input the size of the stack: ";
cin >> size; // Take input for the size of the stack
Stack stk(size); // Create a stack of the given size
cout << "\nInput some elements onto the stack:";
stk.push(1);
stk.push(3);
stk.push(5);
stk.push(7);
stk.push(4);
stk.display(); // Display the elements of the stack
cout << "\nAfter sorting the said stack elements:";
sort_stack(stk.arra, stk.top); // Sort the stack elements in descending order
stk.display(); // Display the sorted elements of the stack
return 0;
}
``````

Sample Output:

```Input the size of the stack: 5

Input some elements onto the stack:
Stack elements are: 4 7 5 3 1

After sorting the said stack elements:
Stack elements are: 1 3 4 5 7
```

Flowchart:

CPP Code Editor: