DEV Community

Cover image for Stack Implementation in C
Yash Desai
Yash Desai

Posted on • Edited on

Stack Implementation in C

#c #stack #algorithms

We need these header files... 

#include <stdio.h>
#include <conio.h>
#include <stdlib.h>
Enter fullscreen mode Exit fullscreen mode

Let's define some constants... 

// constants
#define MAX 5              // Max capacity of a stack
#define ERR "\x1B[31m"     // Error Color
#define SUCCESS "\x1B[32m" // Success Color
#define RESET "\033[0m"    // Reset Color
Enter fullscreen mode Exit fullscreen mode

Constants defined in above lines of code such as ERR,SUCCESS and RESET will be used to color the text of printf(). MAX defines the maximum capacity of the stack

Now we'll declare a stack... 

//declaration of stack
typedef struct stack
{
    int entry[MAX];
    int top;
} stack;
Enter fullscreen mode Exit fullscreen mode

Initialization of stack 

//stack initialization
void init(stack *sptr)
{
    sptr->top = 0;
}
Enter fullscreen mode Exit fullscreen mode

A function to check if Stack is empty... 

//checking stack is empty or not.
int isEmpty(stack *sptr)
{
    if (sptr->top == 0)
        return (1);
    else
        return (0);
}
Enter fullscreen mode Exit fullscreen mode

A function to check if stack is overflowed... 

//checking stack is full or not.
int isFull(stack *sptr)
{
    if (sptr->top == MAX)
        return (1);
    else
        return (0);
}
Enter fullscreen mode Exit fullscreen mode

A function to push/insert a new element into the stack... 

//Inserting element into stack
void push(stack *sptr)
{
    int item;
    if (isFull(sptr))
        printf(ERR "\tSTACK IS FULL" RESET);
    else
    {
        printf("\n\tEnter the element: ");
        scanf("%d", &item);
        sptr->entry[sptr->top] = item;
        sptr->top++;
    }
}
Enter fullscreen mode Exit fullscreen mode

A function to pop/remove elements from the stack... 

//Deleting element from the stack
void pop(stack *sptr)
{
    int item;

    if (isEmpty(sptr))
        printf(ERR "\tSTACK IS EMPTY" RESET);
    else
    {
        sptr->top--;
        item = (sptr->entry[sptr->top]);
        printf(SUCCESS "\t%d HAS BEEN REMOVED" RESET, item);
    }
}
Enter fullscreen mode Exit fullscreen mode

A function to traverse though the stack or print all the elements of the stack 

//Traversing the elements of stack
void traverse(stack *sptr)
{
    if (isEmpty(sptr))
        printf(ERR "\tSTACK IS EMPTY" RESET);
    else
    {
        int i;

        for (i = sptr->top - 1; i >= 0; i--)
            printf("\t-> %d\n", sptr->entry[i]);
    }
}
Enter fullscreen mode Exit fullscreen mode

And finally the main() function... 

int main()
{
    stack s;
    int choice;

    init(&s);

    do
    {
        printf("\n 1. PUSH");
        printf("\n 2. POP");
        printf("\n 3. TRAVERSE");
        printf("\n 4. EXIT");
        printf("\n\nEnter the choice: ");
        scanf(" %d", &choice);
        switch (choice)
        {
        case 1:
            push(&s);
            break;
        case 2:
            pop(&s);
            break;
        case 3:
            traverse(&s);
            break;
        case 4:
            exit(0);
            break;
        default:
            printf(ERR "\tWRONG CHOICE" RESET);
        }
    } while (1);

    return 0;
    getch();
}
Enter fullscreen mode Exit fullscreen mode

Output

Alt Text

Alt Text

Pushed 5 elements to the stack. (max capacity=5)

Alt Text

Alt Text

Removed two elements from the stack

Alt Text

Removed all elements until the stack is empty

Alt Text

Enjoy :)

Top comments (2)

Collapse
 
clavinjune profile image
Clavin June •

You can do this btw

//checking stack is empty or not.
int isEmpty(stack *sptr)
{
    return !sptr->top;
}
Enter fullscreen mode Exit fullscreen mode

I think you shouldn't do traverse in stack.

Collapse
 
yashdesai profile image
Yash Desai •

Yes, I do agree with you. Thanks for correction!

Read next

lokesh_singh profile image

The Hidden Algorithms Behind Your Social Media Feed 🤯

lokesh singh tanwar -

bonaogeto profile image

The Complete [2024] Guide to Data Structures and Algorithms

Bonaventure Ogeto -

williams-37 profile image

Understanding Time Complexity in Python Functions

Williams -

nozibul_islam_113b1d5334f profile image

DSA: Recursion - Expanded Questions

Nozibul Islam -