C Exercises: Check a stack is full or not

Last update on August 04 2025 13:04:04 (UTC/GMT +8 hours)

3. Array Stack Capacity Checks

Write a C program to check a stack is full or not using an array with push and pop operations.

Sample Solution:

C Code:

#include <stdio.h>
#include <stdlib.h>
#define MAX_SIZE 3

// Function to create an empty stack
int* createStack() {
    int *stack = (int*) malloc(MAX_SIZE * sizeof(int));
    return stack;
}

// Check if the stack is empty
int isEmpty(int top) {
    return (top == -1);
}

// Check if the stack is full
int isFull(int top) {
    return (top == MAX_SIZE - 1);
}

// Function to push an element to the stack
void push(int *stack, int *top, int item) {
    if (isFull(*top)) {
        printf("Stack is full!\n");
        return;
    }
    stack[++(*top)] = item;
}

// Function to pop an element from the stack
int pop(int *stack, int *top) {
    if (isEmpty(*top)) {
        printf("Stack is empty!\n");
        return -1;
    }
    return stack[(*top)--];
}

int main() {
    // Creating stack and variables to manage it
    int *stack = createStack();
    int top = -1;
    printf("Stack size: %d", MAX_SIZE);

    // Pushing elements to the stack
    push(stack, &top, 1);
    push(stack, &top, 2);
    push(stack, &top, 3);

    // Displaying the original stack
    printf("\nOriginal Stack: ");
    for (int i = 0; i <= top; i++) {
        printf("%d ", stack[i]);
    } 

    // Demonstrating stack overflow condition by trying to push another value
    printf("\nPush another value and check if the stack is full or not!\n");
    push(stack, &top, 4);

    free(stack); // Freeing memory allocated for the stack

    // Creating another stack and variables to manage it
    int *stack1 = createStack();
    int top1 = -1, result;
    printf("\nStack size: %d", MAX_SIZE);

    // Pushing elements to the new stack
    push(stack1, &top1, 10);
    push(stack1, &top1, 20);

    // Displaying the original stack
    printf("\nOriginal Stack: ");
    for (int i = 0; i <= top1; i++) {
        printf("%d ", stack1[i]);
    } 

    // Checking if the second stack is full or not
    printf("\nCheck the said stack is full or not!\n");
    result = isFull(top1);
    if (result == 1)
        printf("Stack is full!");
    else
        printf("Stack is not full!");

    free(stack1); // Freeing memory allocated for the second stack
    return 0;
}

Output:

Stack size: 3
Original Stack: 1 2 3 
Push another value and check if the stack is full or not!
Stack is full!

Stack size: 3
Original Stack: 10 20 
Check the said stack is full or not!
Stack is not full!

Flowchart:

Flowchart: Check a stack is full or not.

For more Practice: Solve these Related Problems:

Write a C program to implement a bounded stack that alerts when it reaches 75% of its capacity.
Write a C program to simulate continuous push operations on an array-based stack and trigger a full-stack error when the limit is reached.
Write a C program to dynamically display the available free space in a fixed-size array-based stack after each operation.
Write a C program to design an array-based stack that supports a "peek capacity" function to check current usage percentage.

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