C Exercises: Implement a stack using a singly linked list

C Stack: Exercise-2 with Solution

Write a C program to implement a stack using a singly linked list.

Sample Solution:

C Code:

#include <stdio.h>
#include <stdlib.h>

// Node structure to represent elements in the stack
struct Node {
    int data;
    struct Node* next;
};

// Stack structure to manage the stack
struct Stack {
    struct Node* top;
};

// Function to create a new node with given data
struct Node* newNode(int data) {
    struct Node* node = (struct Node*) malloc(sizeof(struct Node));
    node->data = data;
    node->next = NULL;
    return node;
}

// Function to create a new stack and initialize it
struct Stack* createStack() {
    struct Stack* stack = (struct Stack*) malloc(sizeof(struct Stack));
    stack->top = NULL;
    return stack;
}

// Function to check if the stack is empty
int isEmpty(struct Stack* stack) {
    return !stack->top; // Returns 1 if the stack is empty, otherwise returns 0
}

// Function to push a value onto the stack
void push_data(struct Stack* stack, int data) {
    printf("\n Push data %d", data);
    struct Node* node = newNode(data);
    node->next = stack->top;
    stack->top = node; // The new node becomes the top of the stack
}

// Function to pop a value from the stack
int pop_data(struct Stack* stack) {
    if (isEmpty(stack)) {
        printf("Stack is empty\n");
        return -1; // Returns -1 if the stack is empty
    }
    struct Node* temp = stack->top;
    int popped = temp->data; // Value to be popped from the top of the stack
    stack->top = temp->next; // Move the top pointer to the next node
    free(temp); // Free the memory of the popped node
    return popped; // Return the popped value
}

int main() {
    // Creating a stack and pushing elements onto it
    struct Stack* stack1 = createStack();
    push_data(stack1, 1);
    push_data(stack1, 2);
    push_data(stack1, 3);
    push_data(stack1, 4);

    // Popping elements from the stack and displaying them
    printf("\n\n Pop data: %d", pop_data(stack1));
    printf("\n Pop data: %d", pop_data(stack1));
    printf("\n Pop data: %d", pop_data(stack1));
    printf("\n Pop data: %d", pop_data(stack1));

    // Checking if a stack is empty or not
    printf("\n\n Check a stack is empty or not?\n");
    struct Stack* stack2 = createStack();
    if (isEmpty(stack2)) {
        printf(" Stack is empty!\n");
    } else {
        printf(" Stack is not empty!\n");
    }
}

Sample Output:

 Push data 1
 Push data 2
 Push data 3
 Push data 4

 Pop data: 4
 Pop data: 3
 Pop data: 2
 Pop data: 1

 Check a stack is empty or not?
 Stack is empty!

Flowchart:

C Programming Code Editor:

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