Question

Examples:

The Lab is divided into a set of example and exercise activities related with this topic and students are required to perform all activities and show (and discuss) the output of activities to the instructor.

Example 1: Implement the Stack Push Operation with Overflow condition

Declare an array of size 5 and implement the Push Operation with overflow condition; you can type the following code as a hint:

            #include<iostream>

            using namespace std ;

            #define MAX 5

            struct Stack {

                        int S[MAX];

                        int top;

};

Stack st;

st.top = -1;

int item;

            if(st.top == (MAX-1))

                        cout<<"Stack Overflow\n" ;

            else     
            {

                        cout<< "Enter the item to be pushed in stack : " ;

                        cin>> item ;

                        st.top++;

                        st.S[st.top] = item;

            }

Complete this implementation as a full program to PUSH as many elements as the user wants (or till the Stack is full).

Example 2: Implement the Stack Pop Operation with Underflow condition

Declare an array of size 5 and implement the Pop operation; you can type the following code as a hint:

            int item;

            if (st.top == -1) /* stack empty condition */

                        cout<< "Stack Underflow\n" ;

            else

            {

                        item = st.S[st.top];

                        st.top-- ;

cout<< "Element popped from stack is :" << item ;

            }

Complete this implementation as a full program to POP as many elements as the user wants (or till the Stack is empty).

Example 3: Display the contents of Stack

Display the contents of Stack; you can type the following code as a hint:  

int i;

if(st.top == -1)

            cout<<"Stack is empty\n" ;

else     

{

            cout<< "Stack elements :\n" ;

            for(i = st.top; i >=0; i--)

                        cout<< st.S[i] ; }

Exercise

Combine all the three examples above to implement one complete program of Stack

Answer 1

CODE -

#include<iostream>

using namespace std ;

#define MAX 5

// DEFINING THE STRUCT STACK

struct Stack {

    int S[MAX];

    int top;

};

// MAIN FUNCTION

main()

{

    Stack st;

    st.top = -1;

    // LOOP TO RUN UNTIL USER EXITS.

    while(true)

    {

        // DISPLAYING THE STACK OPERATIONS MENU

        cout << "\nStack Operations Menu" << endl << endl;

        cout << "1. Push \n2. Pop \n3. Display Stack \n4. Exit" << endl;

        // TAKING CHOICE AS INPUT FROM USER.

        cout << "Enter your choice: ";

        int choice;

        cin >> choice;

        if(choice == 1)

        {

            int item;

            // DISPLAYING "STACK OVERFLOW" MESSAGE IF STACK IS FULL AND USER TRIES TO PUSH ELEMENT TO THE STACK

            if(st.top == (MAX-1))

                cout<<"\nStack Overflow\n" ;

            // TAKING ELEMENT AS INPUT AND PUSHING IT TO THE STACK IF THE STACK IS NOT FULL

            else

            {

                cout<< "\nEnter the item to be pushed in stack : " ;

                cin>> item ;

                st.top++;

                st.S[st.top] = item;

            }

        }

        else if(choice == 2)

        {

            int item;

            // DISPLAYING "STACK UNDERFLOW" MESSAGE IF STACK IS EMPTY AND USER TRIES TO POP ELEMENT FROM THE STACK

            if (st.top == -1) /* stack empty condition */

                cout<< "\nStack Underflow\n" ;

            // POPPING OUT TOP ELEMENT FROM THE STACK IF THE STACK IS NOT EMPTY

            else

            {

                item = st.S[st.top];

                st.top-- ;

                cout<< "\nElement popped from stack is :" << item << endl;

            }

        }

        else if(choice == 3)

        {

            int i;

            // DISPLAYING "STACK IS EMPTY" MESSAGE IF STACK IS EMPTY AND USER TRIES TO DISPLAY THE STACK

            if(st.top == -1)

                cout<<"\nStack is empty\n" ;

            // DISPLAYING THE STACK ELEMENTS IF STACK IS NOT EMPTY

            else     

            {

                cout<< "\nStack elements :\n" ;

                for(i = st.top; i >=0; i--)

                    cout<< st.S[i] << " ";

                cout << endl;

            }

        }

        // EXITING THE LOOP AND ULTIMATELY THE PROGRAM IF USER ENTERS 4 AS THEIR CHOICE

        else if(choice == 4)

            break;

        // DISPLAYING ERROR MESSAGE IF USER ENTERS INVALID CHOICE.

        else

        {

            cout << "\nInvalid Choice!" << endl << endl;

        }

    }

}

SCREENSHOTS -

CODE -

OUTPUT -

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